diff --git a/Makefile b/Makefile
index dcb2124..b5f5fcd 100644
--- a/Makefile
+++ b/Makefile
@@ -1,14 +1,15 @@
 # path to RETRO68
-RETRO68=/Users/zane/Retro68-build/toolchain
+RETRO68=~/Retro68-build/toolchain
 
-PREFIX=$(RETRO68)/m68k-apple-macos
-AS=$(RETRO68)/bin/m68k-apple-macos-as
-CC=$(RETRO68)/bin/m68k-apple-macos-gcc
-LD=$(RETRO68)/bin/m68k-apple-macos-ld
-OBJCOPY=$(RETRO68)/bin/m68k-apple-macos-objcopy
-OBJDUMP=$(RETRO68)/bin/m68k-apple-macos-objdump
+PREFIX=$(RETRO68)/bin/m68k-apple-macos
+AS=$(PREFIX)-as
+CC=$(PREFIX)-gcc
+LD=$(PREFIX)-ld
+OBJCOPY=$(PREFIX)-objcopy
+OBJDUMP=$(PREFIX)-objdump
+CFLAGS=-march=68030 -c -Os
 
-all: bin/rom16M_swap.bin obj/rdisk1M5.s obj/rdisk7M5.s obj/driver1M5.s obj/driver7M5.s obj/entry_rel.sym obj/driver_abs.sym
+all: bin/rom16M_swap.bin obj/rdisk7M5.s obj/driver7M5.s obj/entry_rel.sym obj/driver_abs.sym
 
 obj:
 	mkdir obj
@@ -24,56 +25,42 @@ obj/entry_rel.sym: obj obj/entry.o
 	$(OBJDUMP) -t obj/entry.o > $@
 
 
-obj/rdisk1M5.o: rdisk.c obj
-	$(CC) -DRDiskSize=1572864 -c -Os $< -o $@
-
 obj/rdisk7M5.o: rdisk.c obj
-	$(CC) -DRDiskSize=7864320 -c -Os $< -o $@
-
-obj/rdisk1M5.s: obj obj/rdisk1M5.o
-	$(OBJDUMP) -d obj/rdisk1M5.o > $@
+	$(CC) -Wall -DRDiskSize=7864320 $(CFLAGS) $< -o $@
 
 obj/rdisk7M5.s: obj obj/rdisk7M5.o
-	$(OBJDUMP) -d obj/rdisk1M5.o > $@
+	$(OBJDUMP) -d obj/rdisk7M5.o > $@
+
+
+obj/spi.o: spi.c obj
+	$(CC) -Wall $(CFLAGS) $< -o $@
+
+obj/spi.s: obj obj/spi.o
+	$(OBJDUMP) -d obj/spi.o > $@
+
+
+obj/sdmmc.o: sdmmc.c obj
+	$(CC) -Wall $(CFLAGS) -Os $< -o $@
+
+obj/sdmmc.s: obj obj/sdmmc.o
+	$(OBJDUMP) -d obj/sdmmc.o > $@
 
 
-obj/driver1M5.o: obj obj/entry.o obj/rdisk1M5.o
-	$(LD) -Ttext=40851D70 -o $@ obj/entry.o obj/rdisk1M5.o
 
 obj/driver7M5.o: obj obj/entry.o obj/rdisk7M5.o
-	$(LD) -Ttext=40851D70 -o $@ obj/entry.o obj/rdisk7M5.o
-
-obj/driver1M5.s: obj obj/driver1M5.o
-	$(OBJDUMP) -d obj/driver1M5.o > $@
+	$(LD) -Ttext=40851D70 -o $@ obj/entry.o obj/rdisk7M5.o obj/spi.o obj/sdmmc.o
 
 obj/driver7M5.s: obj obj/driver7M5.o
 	$(OBJDUMP) -d obj/driver7M5.o > $@
 
-obj/driver_abs.sym: obj obj/driver1M5.o
-	$(OBJDUMP) -t obj/driver1M5.o > $@
+obj/driver_abs.sym: obj obj/driver7M5.o
+	$(OBJDUMP) -t obj/driver7M5.o > $@
 
 
-bin/driver1M5.bin: bin obj/driver1M5.o
-	$(OBJCOPY) -O binary obj/driver1M5.o $@
-
 bin/driver7M5.bin: bin obj/driver7M5.o
 	$(OBJCOPY) -O binary obj/driver7M5.o $@
 
-
-bin/rom2M.bin: baserom.bin RDisk1M5.dsk bin bin/driver1M5.bin obj/driver_abs.sym obj/entry_rel.sym 
-	cp baserom.bin $@ # Copy base rom
-	# Patch driver
-	dd if=bin/driver1M5.bin of=$@ bs=1 seek=335248 skip=32 conv=notrunc # Copy driver code
-	printf '\x78' | dd of=$@ bs=1 seek=335168 count=1 conv=notrunc # Set resource flags
-	printf '\x4F' | dd of=$@ bs=1 seek=335216 count=1 conv=notrunc # Set driver flags
-	cat obj/entry_rel.sym | grep "DOpen" | cut -c5-8 | xxd -r -p - | dd of=$@ bs=1 seek=335224 count=2 conv=notrunc
-	cat obj/entry_rel.sym | grep "DPrime" | cut -c5-8 | xxd -r -p - | dd of=$@ bs=1 seek=335226 count=2 conv=notrunc
-	cat obj/entry_rel.sym | grep "DControl" | cut -c5-8 | xxd -r -p - | dd of=$@ bs=1 seek=335228 count=2 conv=notrunc
-	cat obj/entry_rel.sym | grep "DStatus" | cut -c5-8 | xxd -r -p - | dd of=$@ bs=1 seek=335230 count=2 conv=notrunc
-	cat obj/entry_rel.sym | grep "DClose" | cut -c5-8 | xxd -r -p - | dd of=$@ bs=1 seek=335232 count=2 conv=notrunc
-	dd if=RDisk1M5.dsk of=$@ bs=1024 seek=512 count=1536 conv=notrunc # copy disk image
-
-bin/rom8M.bin: baserom.bin RDisk7M5.dsk bin bin/driver7M5.bin obj/driver_abs.sym obj/entry_rel.sym 
+bin/rom8M.bin: bin baserom.bin RDisk7M5.dsk bin bin/driver7M5.bin obj/driver_abs.sym obj/entry_rel.sym 
 	cp baserom.bin $@ # Copy base rom
 	# Patch driver
 	dd if=bin/driver7M5.bin of=$@ bs=1 seek=335248 skip=32 conv=notrunc # Copy driver code
@@ -86,15 +73,15 @@ bin/rom8M.bin: baserom.bin RDisk7M5.dsk bin bin/driver7M5.bin obj/driver_abs.sym
 	cat obj/entry_rel.sym | grep "DClose" | cut -c5-8 | xxd -r -p - | dd of=$@ bs=1 seek=335232 count=2 conv=notrunc
 	dd if=RDisk7M5.dsk of=$@ bs=1024 seek=512 count=7680 conv=notrunc # copy disk image
 
-bin/rom8M_swap.bin: bin/rom8M.bin
+bin/rom8M_swap.bin: bin bin/rom8M.bin
 	dd if=bin/rom8M.bin of=$@ conv=swab # swap bytes
 
-bin/rom2M_swap.bin: bin/rom2M.bin
-	dd if=bin/rom2M.bin of=$@ conv=swab # swap bytes
+bin/iisi_swap.bin: bin iisi.bin
+	dd if=iisi.bin of=$@ conv=swab # swap bytes
 
-bin/rom16M_swap.bin: bin/rom2M_swap.bin bin/rom8M_swap.bin
+bin/rom16M_swap.bin: bin/iisi_swap.bin bin/rom8M_swap.bin
 	cat bin/rom8M_swap.bin > $@
-	cat bin/rom2M_swap.bin >> $@
+	cat bin/iisi_swap.bin >> $@
 
 
 .PHONY: clean
diff --git a/entry.s b/entry.s
index a64a11b..ea864cf 100644
--- a/entry.s
+++ b/entry.s
@@ -4,33 +4,57 @@
 .EQU	kioResult,	16
 .EQU	kcsCode,	26
 .EQU	JIODone,	0x08FC
+.GLOBAL RDiskSig
+.GLOBAL RDiskDBGNamePos
+.GLOBAL RDiskDBGDisPos
+.GLOBAL RDiskDBGDisByte
+.GLOBAL RDiskCDRNamePos
+.GLOBAL RDiskCDRDisPos
+.GLOBAL RDiskCDRDisByte
 
 dc.l	0x00000000, 0x00000000, 0x00000000, 0x00000000
 dc.l	0x00000000, 0x00000000, 0x00000000, 0x00000000
+
+RDiskSig:
 .ascii	"\5RDisk\0"
 .align 4
+RDiskDBGDisPos:
+dc.l 0x00000031
+RDiskCDRDisPos:
+dc.l 0x00012CAF
+RDiskDBGNameAddr:
+dc.l 0x4088002A
+RDiskCDRNameAddr:
+dc.l 0x40892C96
+RDiskDBGDisByte:
+dc.b 0x44
+RDiskCDRDisByte:
+dc.b 0x44
+RDiskRAMRequired:
+.ascii	"16"
 
+.align 4
 DOpen:
 	movem.l		%A0-%A1, -(%SP)
-	bsr			RDiskOpen
+	bsr			RDOpen
 	movem.l		(%SP)+, %A0-%A1
 	rts
 
 DClose:
 	movem.l		%A0-%A1, -(%SP)
-	bsr			RDiskClose
+	bsr			RDClose
 	movem.l		(%SP)+, %A0-%A1
 	rts
 
 DPrime:
 	movem.l		%A0-%A1, -(%SP)
-	bsr			RDiskPrime
+	bsr			RDPrime
 	movem.l		(%SP)+, %A0-%A1
 	bra.b		IOReturn
 
 DControl:
 	movem.l		%A0-%A1, -(%SP)
-	bsr			RDiskControl
+	bsr			RDCtl
 	movem.l		(%SP)+, %A0-%A1
 	cmpi.w		#killCode, kcsCode(%A0)
 	bne.b		IOReturn
@@ -38,7 +62,7 @@ DControl:
 
 DStatus:
 	movem.l		%A0-%A1, -(%SP)
-	bsr			RDiskStatus
+	bsr			RDStat
 	movem.l		(%SP)+, %A0-%A1
 
 IOReturn:
diff --git a/rdisk.c b/rdisk.c
deleted file mode 100644
index 3a55e8b..0000000
--- a/rdisk.c
+++ /dev/null
@@ -1,285 +0,0 @@
-#include <Memory.h>
-#include <Devices.h>
-#include <Files.h>
-#include <Disks.h>
-#include <Errors.h>
-#include <Events.h>
-#include <OSUtils.h>
-
-#include "rdisk.h"
-
-// Decode keyboard/PRAM settings
-static void RDiskDecodeSettings(RDiskStorage_t *c, Ptr unmount, Ptr mount, Ptr ram) {
-	// Decode settings
-	if (RDiskIsRPressed()) { // R boots from ROM disk
-		*unmount = 0; // Don't unmount so we boot from this drive
-		*mount = 0; // No need to mount later since we are boot disk
-		*ram = RDiskIsAPressed(); // A enables RAM disk
-	} else {
-		// Read PRAM
-		char legacy_startup, legacy_ram;
-		RDiskReadXPRAM(1, 4, &legacy_startup);
-		RDiskReadXPRAM(1, 5, &legacy_ram);
-		if (legacy_startup & 1) { // Boot from ROM disk
-			*unmount = 0; // Don't unmount so we boot from this drive
-			*mount = 0; // No need to mount later since we are boot disk
-			*ram = legacy_ram & 1;
-		} else if (legacy_startup & 2) { // Mount ROM disk
-			*unmount = 1; // Unmount to not boot from our disk
-			*mount = 1; // Mount in accRun
-			*ram = legacy_ram & 1;
-		} else {
-			*unmount = 1; // Unmount
-			*mount = 0; // Don't mount again
-			*ram = 0; // Don't allocate RAM disk
-		}
-	}
-}
-
-// Switch to 32-bit mode and copy
-#pragma parameter RDiskCopy24(__A0, __A1, __D0)
-void RDiskCopy24(Ptr sourcePtr, Ptr destPtr, unsigned long byteCount) {
-	char mode = true32b;
-	SwapMMUMode(&mode);
-	BlockMove(sourcePtr, destPtr, byteCount);
-	SwapMMUMode(&mode);
-}
-
-// Figure out the first available drive number >= 5
-static int RDiskFindDrvNum() {
-	DrvQElPtr dq;
-	int drvNum = 5;
-	for (dq = (DrvQElPtr)(GetDrvQHdr())->qHead; dq; dq = (DrvQElPtr)dq->qLink) {
-		if (dq->dQDrive >= drvNum) { drvNum = dq->dQDrive + 1; }
-	}
-	return drvNum;
-}
-
-#pragma parameter __D0 RDiskOpen(__A0, __A1)
-OSErr RDiskOpen(IOParamPtr p, DCtlPtr d) {
-	int drvNum;
-	RDiskStorage_t *c;
-	char legacy_startup, legacy_ram;
-
-	// Do nothing if already opened
-	if (d->dCtlStorage) { return noErr; }
-
-	// Do nothing if inhibited
-	RDiskReadXPRAM(1, 4, &legacy_startup);
-	RDiskReadXPRAM(1, 5, &legacy_ram);
-	if ((legacy_startup & 0x07) == 0x04) { return noErr; } 
-
-	// Allocate storage struct
-	d->dCtlStorage = NewHandleSysClear(sizeof(RDiskStorage_t));
-	if (!d->dCtlStorage) { return openErr; }
-
-	// Lock our storage struct and get master pointer
-	HLock(d->dCtlStorage);
-	c = *(RDiskStorage_t**)d->dCtlStorage;
-
-	// Find first available drive number
-	drvNum = RDiskFindDrvNum();
-
-	// Set drive status
-	//c->status.track = 0;
-	c->status.writeProt = -1; // nonzero is write protected
-	c->status.diskInPlace = 8; // 8 is nonejectable disk
-	c->status.installed = 1; // drive installed
-	//c->status.sides = 0;
-	//c->status.qType = 1;
-	c->status.dQDrive = drvNum;
-	//c->status.dQFSID = 0;
-	c->status.dQRefNum = d->dCtlRefNum;
-	c->status.driveSize = RDiskSize / 512;
-	//c->status.driveS1 = (RDiskSize / 512) >> 16;
-
-	// Decompress icon
-	#ifdef RDISK_COMPRESS_ICON_ENABLE
-	char *src = &RDiskIconCompressed[0];
-	char *dst = &c->icon[0];
-	UnpackBits(&src, &dst, RDISK_ICON_SIZE);
-	#endif
-
-	// Add drive to drive queue and return
-	RDiskAddDrive(c->status.dQRefNum, drvNum, (DrvQElPtr)&c->status.qLink);
-	return noErr;
-}
-
-// Init is called at beginning of first prime (read/write) call
-static void RDiskInit(IOParamPtr p, DCtlPtr d, RDiskStorage_t *c) {
-	char unmountEN, mountEN, ramEN;
-	// Mark init done
-	c->initialized = 1;
-	// Decode settings
-	RDiskDecodeSettings(c, &unmountEN, &mountEN, &ramEN);
-
-	// If RAM disk enabled, try to allocate RAM disk buffer if not already
-	if (ramEN & !c->ramdisk) {
-		if (*MMU32bit) { // 32-bit mode
-			unsigned long minBufPtr, newBufPtr;
-			// Compute if there is enough high memory
-			minBufPtr = ((unsigned long)*MemTop / 2) + 1024;
-			newBufPtr = (unsigned long)*BufPtr - RDiskSize;	
-			if (newBufPtr > minBufPtr && (unsigned long)*BufPtr > newBufPtr) {
-				// Allocate RAM disk buffer by lowering BufPtr
-				*BufPtr = (Ptr)newBufPtr;
-				// Set RAM disk buffer pointer.
-				c->ramdisk = *BufPtr;
-				// Copy ROM disk image to RAM disk
-				BlockMove(RDiskBuf, c->ramdisk, RDiskSize);
-				// Clearing write protect marks RAM disk enabled
-				c->status.writeProt = 0;
-			}
-		} else { // 24-bit mode
-			// Put RAM disk just past 8MB
-			c->ramdisk = (Ptr)(8 * 1024 * 1024);
-			// Copy ROM disk image to RAM disk
-			copy24(RDiskBuf, c->ramdisk, RDiskSize);
-			// Clearing write protect marks RAM disk enabled
-			c->status.writeProt = 0;
-			//FIXME: what if we don't have enough RAM? 
-			// Will this wrap around and overwrite low memory?
-			// That's not the worst, since the system would just crash,
-			// but it would be better to switch to read-only status
-		}
-	}
-
-	// Unmount if not booting from ROM disk
-	if (unmountEN) { c->status.diskInPlace = 0; }
-
-	// If mount enabled, enable accRun to post disk inserted event later
-	if (mountEN) { 
-		d->dCtlDelay = 150; // Set accRun delay (150 ticks is 2.5 sec.)
-		d->dCtlFlags |= dNeedTimeMask; // Enable accRun
-	}
-}
-
-#pragma parameter __D0 RDiskPrime(__A0, __A1)
-OSErr RDiskPrime(IOParamPtr p, DCtlPtr d) {
-	RDiskStorage_t *c;
-	char cmd;
-	Ptr disk;
-
-	// Return disk offline error if dCtlStorage null
-	if (!d->dCtlStorage) { return notOpenErr; }
-	// Dereference dCtlStorage to get pointer to our context
-	c = *(RDiskStorage_t**)d->dCtlStorage;
-
-	// Initialize if this is the first prime call
-	if (!c->initialized) { RDiskInit(p, d, c); }
-
-	// Return disk offline error if virtual disk not inserted
-	if (!c->status.diskInPlace) { return offLinErr; }
-
-	// Get pointer to RAM or ROM disk buffer
-	disk = (c->ramdisk ? c->ramdisk : RDiskBuf) + d->dCtlPosition;
-	//  Bounds checking
-	if (d->dCtlPosition >= RDiskSize || p->ioReqCount >= RDiskSize || 
-		d->dCtlPosition + p->ioReqCount >= RDiskSize) { return paramErr; }
-
-	// Service read or write request
-	cmd = p->ioTrap & 0x00FF;
-	if (cmd == aRdCmd) { // Read
-		// Read from disk into buffer.
-		if (*MMU32bit) { BlockMove(disk, p->ioBuffer, p->ioReqCount); }
-		else { copy24(disk, StripAddress(p->ioBuffer), p->ioReqCount); }
-	} else if (cmd == aWrCmd) { // Write
-		// Fail if write protected or RAM disk buffer not set up
-		if (c->status.writeProt || !c->ramdisk) { return wPrErr; }
-		// Write from buffer into disk.
-		if (*MMU32bit) { BlockMove(p->ioBuffer, disk, p->ioReqCount); }
-		else { copy24(StripAddress(p->ioBuffer), disk, p->ioReqCount); }
-	} else { return noErr; } //FIXME: Fail if cmd isn't read or write?
-
-	// Update count and position/offset, then return
-	d->dCtlPosition += p->ioReqCount;
-	p->ioActCount = p->ioReqCount;
-	return noErr;
-}
-
-#pragma parameter __D0 RDiskControl(__A0, __A1)
-OSErr RDiskControl(CntrlParamPtr p, DCtlPtr d) {
-	RDiskStorage_t *c;
-	// Fail if dCtlStorage null
-	if (!d->dCtlStorage) { return notOpenErr; }
-	// Dereference dCtlStorage to get pointer to our context
-	c = *(RDiskStorage_t**)d->dCtlStorage;
-	// Handle control request based on csCode
-	switch (p->csCode) {
-		case killCode:
-			return noErr;
-		case kFormat:
-			if (!c->status.diskInPlace || c->status.writeProt ||
-				!c->ramdisk) { return controlErr; } 
-			long zero[32];
-			for (int i = 0; i < 32; i++) { zero[i] = 0; }
-			for (int i = 0; i < 32; i++) {
-				copy24((Ptr)zero, c->ramdisk + i * sizeof(zero), sizeof(zero));
-			}
-			return noErr;
-		case kVerify:
-			if (!c->status.diskInPlace) { return controlErr; }
-			return noErr;
-		case kEject:
-			// "Reinsert" disk if ejected illegally
-			if (c->status.diskInPlace) { 
-				PostEvent(diskEvt, c->status.dQDrive);
-			}
-			return controlErr; // Eject not allowed so return error
-		case accRun:
-			d->dCtlFlags &= ~dNeedTimeMask; // Disable accRun
-			c->status.diskInPlace = 8; // 8 is nonejectable disk
-			PostEvent(diskEvt, c->status.dQDrive); // Post disk inserted event
-			return noErr;
-		case kDriveIcon: case kMediaIcon: // Get icon
-			#ifdef RDISK_COMPRESS_ICON_ENABLE
-			*(Ptr*)p->csParam = (Ptr)c->icon;
-			#else
-			*(Ptr*)p->csParam = (Ptr)RDiskIcon;
-			#endif
-			return noErr;
-		case kDriveInfo:
-			//  high word (bytes 2 & 3) clear
-			//  byte 1 = primary + fixed media + internal
-			//  byte 0 = drive type (0x10 is RAM disk) / (0x11 is ROM disk)
-			if (c->status.writeProt) { *(long*)p->csParam = 0x00000410; }
-			else { *(long*)p->csParam = 0x00000411; }
-			return noErr;
-		case 24: // Return SCSI partition size
-			*(long*)p->csParam = RDiskSize / 512;
-			return noErr;
-		case 2351: // Post-boot
-			c->initialized = 1; // Skip initialization
-			d->dCtlDelay = 30; // Set accRun delay (30 ticks is 0.5 sec.)
-			d->dCtlFlags |= dNeedTimeMask; // Enable accRun
-			return noErr;
-		default: return controlErr;
-	}
-}
-
-#pragma parameter __D0 RDiskStatus(__A0, __A1)
-OSErr RDiskStatus(CntrlParamPtr p, DCtlPtr d) {
-	RDiskStorage_t *c;
-	// Fail if dCtlStorage null
-	if (!d->dCtlStorage) { return notOpenErr; }
-	// Dereference dCtlStorage to get pointer to our context
-	c = *(RDiskStorage_t**)d->dCtlStorage;
-	// Handle status request based on csCode
-	switch (p->csCode) {
-		case kDriveStatus:
-			BlockMove(*d->dCtlStorage, &p->csParam, sizeof(DrvSts2));
-			return noErr;
-		default: return statusErr;
-	}
-}
-
-#pragma parameter __D0 RDiskClose(__A0, __A1)
-OSErr RDiskClose(IOParamPtr p, DCtlPtr d) {
-	// If dCtlStorage not null, dispose of it
-	if (!d->dCtlStorage) { return noErr; }
-	RDiskStorage_t *c = *(RDiskStorage_t**)d->dCtlStorage;
-	HUnlock(d->dCtlStorage);
-	DisposeHandle(d->dCtlStorage);
-	d->dCtlStorage = NULL;
-	return noErr;
-}
diff --git a/rdisk.h b/rdisk.h
deleted file mode 100644
index 689ee88..0000000
--- a/rdisk.h
+++ /dev/null
@@ -1,195 +0,0 @@
-#ifndef RDISK_H
-#define RDISK_H
-
-//#define RDiskSize (0x00180000L)
-#define RDiskBuf ((char*)0x40880000)
-#define BufPtr ((Ptr*)0x10C)
-#define MemTop ((Ptr*)0x108)
-#define MMU32bit ((char*)0xCB2)
-
-#pragma parameter __D0 RDiskReadXPRAM(__D0, __D1, __A0)
-OSErr RDiskReadXPRAM(short numBytes, short whichByte, Ptr dest) = {0x4840, 0x3001, 0xA051};
-
-#pragma parameter __D0 RDiskAddDrive(__D1, __D0, __A0)
-OSErr RDiskAddDrive(short drvrRefNum, short drvNum, DrvQElPtr dq) = {0x4840, 0x3001, 0xA04E};
-
-static inline char RDiskIsRPressed() { return *((char*)0x175) & 0x80; }
-static inline char RDiskIsAPressed() { return *((char*)0x174) & 0x01; }
-
-typedef void (*RDiskCopy_t)(Ptr, Ptr, unsigned long);
-#define copy24(s, d, b) { RDiskCopy_t copy24 = (RDiskCopy_t)RDiskCopy24; copy24(s, d, b); }
-
-//#define RDISK_COMPRESS_ICON_ENABLE
-#define RDISK_ICON_SIZE (285)
-typedef struct RDiskStorage_s {
-	DrvSts2 status;
-	char initialized;
-	Ptr ramdisk;
-	#ifdef RDISK_COMPRESS_ICON_ENABLE
-	char icon[RDISK_ICON_SIZE];
-	#endif
-} RDiskStorage_t;
-
-#define PackBits_Repeat(count) (-1 * (count - 1))
-#define PackBits_Literal(count) (count - 1)
-
-#define RDISK_COMPRESSED_ICON_SIZE (87)
-#ifdef RDISK_COMPRESS_ICON_ENABLE
-#include <Quickdraw.h>
-const char const RDiskIconCompressed[RDISK_COMPRESSED_ICON_SIZE] = {
-	PackBits_Repeat(76), 0b00000000, /*
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000, */
-	PackBits_Repeat(4), 0b11111111, /*
-	0b11111111, 0b11111111, 0b11111111, 0b11111111, */
-	PackBits_Literal(36),
-	0b10000000, 0b00000000, 0b00000000, 0b00000001,
-	0b10001111, 0b00011110, 0b00111100, 0b01111001,
-	0b10001001, 0b00010010, 0b00100100, 0b01001001,
-	0b10001001, 0b00010010, 0b00100100, 0b01001001,
-	0b10001001, 0b00010010, 0b00100100, 0b01001001,
-	0b10001111, 0b00011110, 0b00111100, 0b01111001,
-	0b11000000, 0b00000000, 0b00000000, 0b00000001,
-	0b01010101, 0b01010101, 0b11010101, 0b01010101,
-	0b01111111, 0b11111111, 0b01111111, 0b11111111,
-	PackBits_Repeat(12), 0b00000000, /*
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000, */
-	
-	PackBits_Repeat(76), 0b00000000, /*
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000, */
-	PackBits_Repeat(32), 0b11111111, /*
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111, */
-	PackBits_Literal(1), 0b01111111, 
-	PackBits_Repeat(3), 0b11111111, /*
-	0b01111111, 0b11111111, 0b11111111, 0b11111111, */
-	PackBits_Literal(1), 0b01111111, 
-	PackBits_Repeat(3), 0b11111111, /*
-	0b01111111, 0b11111111, 0b11111111, 0b11111111, */
-	PackBits_Repeat(12), 0b00000000, /*
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000, */
-	PackBits_Literal(29),
-	27, 'G', 'a', 'r', 'r', 'e', 't', 't', '\'', 's', ' ', 
-	'W', 'o', 'r', 'k', 's', 'h', 'o', 'p', ' ', 
-	'R', 'O', 'M', ' ', 'D', 'i', 's', 'k', 0
-};
-#else
-const char const RDiskIcon[RDISK_ICON_SIZE] = {
-	// Icon
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b10000000, 0b00000000, 0b00000000, 0b00000001,
-	0b10001111, 0b00011110, 0b00111100, 0b01111001,
-	0b10001001, 0b00010010, 0b00100100, 0b01001001,
-	0b10001001, 0b00010010, 0b00100100, 0b01001001,
-	0b10001001, 0b00010010, 0b00100100, 0b01001001,
-	0b10001111, 0b00011110, 0b00111100, 0b01111001,
-	0b11000000, 0b00000000, 0b00000000, 0b00000001,
-	0b01010101, 0b01010101, 0b11010101, 0b01010101,
-	0b01111111, 0b11111111, 0b01111111, 0b11111111,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	// Mask
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b11111111, 0b11111111, 0b11111111, 0b11111111,
-	0b01111111, 0b11111111, 0b11111111, 0b11111111,
-	0b01111111, 0b11111111, 0b11111111, 0b11111111,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	0b00000000, 0b00000000, 0b00000000, 0b00000000,
-	27, 'G', 'a', 'r', 'r', 'e', 't', 't', '\'', 's', ' ', 
-	'W', 'o', 'r', 'k', 's', 'h', 'o', 'p', ' ', 
-	'R', 'O', 'M', ' ', 'D', 'i', 's', 'k', 0
-};
-#endif
-
-#endif
diff --git a/rombus.c b/rombus.c
new file mode 100644
index 0000000..7a295ab
--- /dev/null
+++ b/rombus.c
@@ -0,0 +1,361 @@
+#include <Memory.h>
+#include <Devices.h>
+#include <Files.h>
+#include <Disks.h>
+#include <Errors.h>
+#include <Events.h>
+#include <OSUtils.h>
+
+#include "rdisk.h"
+
+// Decode keyboard/PRAM settings
+static void RDDecodeSettings(Ptr recoveryEN, Ptr unmountEN, Ptr mountEN) {
+	// Read PRAM
+	char legacy_startup;
+	RBReadXPRAM(1, 4, &legacy_startup);
+
+	// Decode settings: boot from recovery, unmount (don't boot), mount (after boot)
+	if (RBIsRPressed()) { // R boots from ROM recovery
+		*recoveryEN = 1; // Enable recovery partition
+		*unmountEN = 0; // Unmount SD so we don't boot from it
+		*mountEN = 1; // Mount SD later
+	} else {
+		*recoveryEN = 0; // Disable recovery partition
+		if (legacy_startup & 0x10) { // Boot from SD disk
+			*unmountEN = 0; // Don't unmount so we boot from this drive
+			*mountEN = 0; // No need to mount later since we are boot disk
+		} else if (legacy_startup & 0x20) { // Mount SD disk under other boot volume
+			*unmountEN = 1; // Unmount to not boot from our disk
+			*mountEN = 1; // Mount in accRun
+		} else {
+			*unmountEN = 1; // Unmount
+			*mountEN = 0; // Don't mount again
+		}
+	}
+}
+
+// Switch to 32-bit mode and copy
+#pragma parameter C24(__A0, __A1, __D0)
+void __attribute__ ((noinline)) C24(Ptr sourcePtr, Ptr destPtr, unsigned long byteCount) {
+	signed char mode = true32b;
+	SwapMMUMode(&mode);
+	BlockMove(sourcePtr, destPtr, byteCount);
+	SwapMMUMode(&mode);
+}
+
+// Switch to 32-bit mode and get
+#pragma parameter __D0 G24(__A2)
+char __attribute__ ((noinline)) G24(Ptr pos) {
+	long ret;
+	signed char mode = true32b;
+	SwapMMUMode(&mode);
+	ret = *pos; // Peek
+	SwapMMUMode(&mode);
+	return ret;
+}
+
+// Switch to 32-bit mode and set
+#pragma parameter S24(__A2, __D3)
+void __attribute__ ((noinline)) S24(Ptr pos, char patch) {
+	signed char mode = true32b;
+	SwapMMUMode(&mode);
+	*pos = patch; // Poke
+	SwapMMUMode(&mode);
+}
+
+// Figure out the first available drive number >= 5
+static int RBFindDrvNum() {
+	DrvQElPtr dq;
+	int drvNum = 5;
+	for (dq = (DrvQElPtr)(GetDrvQHdr())->qHead; dq; dq = (DrvQElPtr)dq->qLink) {
+		if (dq->dQDrive >= drvNum) { drvNum = dq->dQDrive + 1; }
+	}
+	return drvNum;
+}
+
+static void RBOpenRDisk(RDiskStorage_t *c) {
+	int drvNum;
+	
+	// Find first available drive number for ROM recovery
+	drvNum = RBFindDrvNum();
+
+	// Set ROM recovery drive status
+	//c->rStatus.track = 0;
+	c->rStatus.writeProt = -1; // nonzero is write protected
+	c->rStatus.diskInPlace = 8; // 8 is nonejectable disk
+	c->rStatus.installed = 1; // drive installed
+	//c->rStatus.sides = 0;
+	//c->rStatus.qType = 1;
+	c->rStatus.dQDrive = drvNum;
+	//c->rStatus.dQFSID = 0;
+	c->rStatus.dQRefNum = d->dCtlRefNum;
+	c->rStatus.driveSize = RDiskSize / 512;
+	//c->rStatus.driveS1 = (RDiskSize / 512) >> 16;
+
+	// Decompress icon
+	#ifdef RDISK_COMPRESS_ICON_ENABLE
+	char *src = &RDiskIconCompressed[0];
+	char *dst = &c->rIcon[0];
+	UnpackBits(&src, &dst, RDISK_ICON_SIZE);
+	#endif
+
+	// Add RDisk to drive queue and return
+	RDiskAddDrive(c->rStatus.dQRefNum, drvNum, (DrvQElPtr)&c->rStatus.qLink);
+}
+
+static void RBOpenSDisk(RDiskStorage_t *c) {
+	int drvNum;
+	
+	// Find first available drive number for SD disk
+	drvNum = RBFindDrvNum();
+
+	// Set SD disk drive status
+	//c->rStatus.track = 0;
+	c->rStatus.writeProt = 0; // 0 is writable
+	c->rStatus.diskInPlace = 8; // 8 is nonejectable disk
+	c->rStatus.installed = 1; // drive installed
+	//c->rStatus.sides = 0;
+	c->rStatus.qType = 1;
+	c->rStatus.dQDrive = drvNum;
+	//c->rStatus.dQFSID = 0;
+	c->rStatus.dQRefNum = d->dCtlRefNum;
+	c->rStatus.driveSize = SDiskSize / 512;
+	c->rStatus.driveS1 = (SDiskSize / 512) >> 16;
+
+	// Decompress icon
+	#ifdef SDISK_COMPRESS_ICON_ENABLE
+	char *src = &SDiskIconCompressed[0];
+	char *dst = &c->sIcon[0];
+	UnpackBits(&src, &dst, SDISK_ICON_SIZE);
+	#endif
+
+	// Add SDisk to drive queue and return
+	RDiskAddDrive(c->rstatus.dQRefNum, drvNum, (DrvQElPtr)&c->sStatus.qLink);
+}
+
+#pragma parameter __D0 RBOpen(__A0, __A1)
+OSErr RBOpen(IOParamPtr p, DCtlPtr d) {
+	RDiskStorage_t *c;
+	char legacy_startup;
+
+	// Do nothing if already opened
+	if (d->dCtlStorage) { return noErr; }
+
+	// Do nothing if inhibited
+	RBReadXPRAM(1, 4, &legacy_startup);
+	if (legacy_startup & 0x40) { return noErr; } 
+
+	// Allocate storage struct
+	d->dCtlStorage = NewHandleSysClear(sizeof(RDiskStorage_t));
+	if (!d->dCtlStorage) { return openErr; }
+
+	// Lock our storage struct and get master pointer
+	HLock(d->dCtlStorage);
+	c = *(RDiskStorage_t**)d->dCtlStorage;
+
+	// Create RDisk and SDisk entries in drive queue, then return
+	RBOpenRDisk(c);
+	RBOpenSDisk(c);
+	return noErr;
+}
+
+// Init is called at beginning of first prime (read/write) call
+static void RBInit(IOParamPtr p, DCtlPtr d, RDiskStorage_t *c) {
+	char recoveryEN, unmountEN, mountEN;
+	// Mark init done
+	c->initialized = 1;
+	// Decode settings
+	RDDecodeSettings(&recoveryEN, &unmountEN, &mountEN);
+
+	// Unmount if not booting from ROM disk
+	if (!recoveryEN) { c->rStatus.diskInPlace = 0; }
+
+	// Unmount if not booting from ROM disk
+	if (unmountEN) { c->SStatus.diskInPlace = 0; }
+
+	// If mount enabled, enable accRun to post disk inserted event later
+	if (mountEN) { 
+		d->dCtlDelay = 150; // Set accRun delay (150 ticks is 2.5 sec.)
+		d->dCtlFlags |= dNeedTimeMask; // Enable accRun
+	}
+}
+
+static OSErr RDPrime(IOParamPtr p, DCtlPtr d) {
+	// Get pointer to correct position in ROM disk buffer
+	Ptr disk = RDiskBuf + d->dCtlPosition;
+
+	// Return disk offline error if virtual disk not inserted
+	if (!c->rStatus.diskInPlace) { return offLinErr; }
+
+	//  Bounds checking
+	if (d->dCtlPosition >= RDiskSize || p->ioReqCount >= RDiskSize || 
+		d->dCtlPosition + p->ioReqCount >= RDiskSize) { return paramErr; }
+
+	// Service read or write request
+	cmd = p->ioTrap & 0x00FF;
+	if (cmd == aRdCmd) {
+		if (*MMU32bit) { BlockMove(disk, p->ioBuffer, p->ioReqCount); }
+		else { copy24(disk, StripAddress(p->ioBuffer), p->ioReqCount); }
+	} else if (cmd == aWrCmd) { return wPrErr;
+	} else { return noErr; } //FIXME: Fail if cmd isn't read or write?
+
+	// Update count and position/offset, then return
+	d->dCtlPosition += p->ioReqCount;
+	p->ioActCount = p->ioReqCount;
+	return noErr;
+}
+
+static OSErr SDPrime(IOParamPtr p, DCtlPtr d) {
+	
+}
+
+#pragma parameter __D0 RBPrime(__A0, __A1)
+OSErr RBPrime(IOParamPtr p, DCtlPtr d) {
+	RDiskStorage_t *c;
+	char cmd;
+
+	// Return disk offline error if dCtlStorage null
+	if (!d->dCtlStorage) { return notOpenErr; }
+	// Dereference dCtlStorage to get pointer to our context
+	c = *(RDiskStorage_t**)d->dCtlStorage;
+
+	// Initialize if this is the first prime call
+	if (!c->initialized) { RBInit(p, d, c); }
+
+	if (p->ioVRefNum == c->sStatus.dQDrive) {
+		return SDPrime(p, d, c);
+	} else if (p->ioVRefNum == c->rStatus.dQDrive) {
+		return RDPrime(p, d, c);
+	} else { return nsvErr; }
+}
+
+static OSErr RDCtl(CntrlParamPtr p, DCtlPtr d, RDiskStorage_t *c) {
+	// Handle control request based on csCode
+	switch (p->csCode) {
+		case kFormat: return controlErr;
+		case kVerify:
+			if (!c->rStatus.diskInPlace) { return controlErr; }
+			return noErr;
+		case kEject:
+			// "Reinsert" disk if ejected illegally
+			if (c->rStatus.diskInPlace) { 
+				PostEvent(diskEvt, c->status.dQDrive);
+			}
+			return controlErr; // Eject not allowed so return error
+		case kDriveIcon: case kMediaIcon: // Get icon
+			#ifdef RDISK_COMPRESS_ICON_ENABLE
+			*(Ptr*)p->csParam = (Ptr)c->rIcon;
+			#else
+			*(Ptr*)p->csParam = (Ptr)RDiskIcon;
+			#endif
+			return noErr;
+		case kDriveInfo:
+			//  high word (bytes 2 & 3) clear
+			//  byte 1 = primary + fixed media + internal
+			//  byte 0 = drive type (0x11 is ROM disk)
+			*(long*)p->csParam = 0x00000411;
+			return noErr;
+		case 24: // Return SCSI partition size
+			*(long*)p->csParam = RDiskSize / 512;
+			return noErr;
+		default: return controlErr;
+	}
+}
+
+static OSErr SDCtl(CntrlParamPtr p, DCtlPtr d, RDiskStorage_t *c) {
+	// Handle control request based on csCode
+	switch (p->csCode) {
+		case kFormat:
+			// FIXME: implement SD format
+			return controlErr;
+		case kVerify:
+			// FIXME: implement SD verify
+			return noErr;
+		case kEject:
+			// "Reinsert" disk if ejected illegally
+			if (c->sStatus.diskInPlace) { 
+				PostEvent(diskEvt, c->sStatus.dQDrive);
+			}
+			return controlErr; // Eject not allowed so return error
+		case kDriveIcon: case kMediaIcon: // Get icon
+			#ifdef SDISK_COMPRESS_ICON_ENABLE
+			*(Ptr*)p->csParam = (Ptr)c->sIcon;
+			#else
+			*(Ptr*)p->csParam = (Ptr)SDiskIcon;
+			#endif
+			return noErr;
+		case kDriveInfo:
+			//  high word (bytes 2 & 3) clear
+			//  byte 1 = primary + fixed media + internal
+			//  byte 0 = drive type (0x01 is unspecified drive)
+			*(long*)p->csParam = 0x00000401;
+			return noErr;
+		case 24: // Return SCSI partition size
+			*(long*)p->csParam = SDiskSize / 512;
+			return noErr;
+		default: return controlErr;
+	}
+}
+
+#pragma parameter __D0 RBCtl(__A0, __A1)
+OSErr RBCtl(CntrlParamPtr p, DCtlPtr d) {
+	RDiskStorage_t *c;
+	// Fail if dCtlStorage null
+	if (!d->dCtlStorage) { return notOpenErr; }
+	// Dereference dCtlStorage to get pointer to our context
+	c = *(RDiskStorage_t**)d->dCtlStorage;
+	// Handle control request based on csCode
+	switch (p->csCode) {
+		case killCode:
+			return noErr;
+		case accRun:
+			d->dCtlFlags &= ~dNeedTimeMask; // Disable accRun
+			c->sStatus.diskInPlace = 8; // 8 is nonejectable disk
+			PostEvent(diskEvt, c->sStatus.dQDrive); // Post disk inserted event
+			return noErr;
+		case 2351: // Post-boot
+			c->initialized = 1; // Skip initialization
+			d->dCtlDelay = 30; // Set accRun delay (30 ticks is 0.5 sec.)
+			d->dCtlFlags |= dNeedTimeMask; // Enable accRun
+			return noErr;
+	}
+
+	// Otherwise, dispatch to correct drive
+	if (p->ioVRefNum == c->sStatus.dQDrive) {
+		return SDCtl(p, d, c);
+	} else if (p->ioVRefNum == c->rStatus.dQDrive) {
+		return RDCtl(p, d, c);
+	} else { return nsvErr; }
+}
+
+#pragma parameter __D0 RBStat(__A0, __A1)
+OSErr RBStat(CntrlParamPtr p, DCtlPtr d) {
+	RDiskStorage_t *c;
+	// Fail if dCtlStorage null
+	if (!d->dCtlStorage) { return notOpenErr; }
+	// Dereference dCtlStorage to get pointer to our context
+	c = *(RDiskStorage_t**)d->dCtlStorage;
+	// Handle status request based on csCode
+	switch (p->csCode) {
+		case kDriveStatus:
+			// Otherwise, copy correct drive status
+			if (p->ioVRefNum == c->sStatus.dQDrive) {
+				BlockMove(&c->sStatus, &p->csParam, sizeof(DrvSts2));
+			} else if (p->ioVRefNum == c->rStatus.dQDrive) {
+				BlockMove(&c->rStatus, &p->csParam, sizeof(DrvSts2));
+			} else { return nsvErr; }
+			return noErr;
+		default: return statusErr;
+	}
+}
+
+#pragma parameter __D0 RBClose(__A0, __A1)
+OSErr RBClose(IOParamPtr p, DCtlPtr d) {
+	// If dCtlStorage not null, dispose of it
+	if (!d->dCtlStorage) { return noErr; }
+	//RDiskStorage_t *c = *(RDiskStorage_t**)d->dCtlStorage;
+	HUnlock(d->dCtlStorage);
+	DisposeHandle(d->dCtlStorage);
+	d->dCtlStorage = NULL;
+	return noErr;
+}
diff --git a/rombus.h b/rombus.h
new file mode 100644
index 0000000..0e02990
--- /dev/null
+++ b/rombus.h
@@ -0,0 +1,179 @@
+#ifndef ROMBUS_H
+#define ROMBUS_H
+
+#define RDiskBuf ((char*)0x408C0000)
+#define SDiskSize (0x80000000L)
+#define BufPtr ((Ptr*)0x10C)
+#define MemTop ((Ptr*)0x108)
+#define MMU32bit ((char*)0xCB2)
+
+#pragma parameter __D0 RBReadXPRAM(__D0, __D1, __A0)
+OSErr RBReadXPRAM(short numBytes, short whichByte, Ptr dest) = {0x4840, 0x3001, 0xA051};
+
+#pragma parameter __D0 RBAddDrive(__D1, __D0, __A0)
+OSErr RBAddDrive(short drvrRefNum, short drvNum, DrvQElPtr dq) = {0x4840, 0x3001, 0xA04E};
+
+static inline char RBIsRPressed() { return *((char*)0x175) & 0x80; }
+
+typedef struct RBStorage_s {
+	DrvSts2 sStatus;
+	DrvSts2 rStatus;
+	char initialized;
+} RBStorage_t;
+
+typedef void (*RDiskCopy_t)(Ptr, Ptr, unsigned long);
+#define copy24(s, d, b) { RDiskCopy_t f = C24; f(s, d, b); }
+
+typedef char (*RDiskPeek_t)(Ptr);
+#define peek24(a, d) { RDiskPeek_t f = G24; d = f(a); }
+
+typedef void (*RDiskPoke_t)(Ptr, char);
+#define poke24(a, d) { RDiskPoke_t f = S24; f(a, d); }
+
+#define RDISK_ICON_SIZE (285)
+const char RDiskIcon[RDISK_ICON_SIZE] = {
+	// Icon
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b10000000, 0b00000000, 0b00000000, 0b00000001,
+	0b10001111, 0b00011110, 0b00111100, 0b01111001,
+	0b10001001, 0b00010010, 0b00100100, 0b01001001,
+	0b10001001, 0b00010010, 0b00100100, 0b01001001,
+	0b10001001, 0b00010010, 0b00100100, 0b01001001,
+	0b10001111, 0b00011110, 0b00111100, 0b01111001,
+	0b11000000, 0b00000000, 0b00000000, 0b00000001,
+	0b01010101, 0b01010101, 0b11010101, 0b01010101,
+	0b01111111, 0b11111111, 0b01111111, 0b11111111,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	// Mask
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b11111111, 0b11111111, 0b11111111, 0b11111111,
+	0b01111111, 0b11111111, 0b11111111, 0b11111111,
+	0b01111111, 0b11111111, 0b11111111, 0b11111111,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	27, 'G', 'a', 'r', 'r', 'e', 't', 't', '\'', 's', ' ', 
+	'W', 'o', 'r', 'k', 's', 'h', 'o', 'p', ' ', 
+	'R', 'O', 'M', ' ', 'D', 'i', 's', 'k', 0
+};
+
+#define SDISK_ICON_SIZE (283)
+const char const SDiskIcon[SDISK_ICON_SIZE] = {
+	// Icon
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b00000000, 0b00000000, 0b00010000,
+	0b00000001, 0b00000001, 0b10000000, 0b11010000,
+	0b00000001, 0b01101101, 0b10110110, 0b11010000,
+	0b00000001, 0b01101101, 0b10110110, 0b11010000,
+	0b00000001, 0b01101101, 0b10110110, 0b11010000,
+	0b00000001, 0b01101101, 0b10110110, 0b11010000,
+	0b00000001, 0b01101101, 0b10110110, 0b11010000,
+	0b00000001, 0b00000000, 0b00000000, 0b00010000,
+	0b00000001, 0b00000000, 0b00000000, 0b00010000,
+	0b00000010, 0b00000000, 0b00000000, 0b00010000,
+	0b00000100, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001110, 0b00000000, 0b00000000, 0b00010000,
+	0b00000010, 0b00000000, 0b00000000, 0b00010000,
+	0b00000010, 0b00000000, 0b00000000, 0b00010000,
+	0b00000010, 0b00000000, 0b00000000, 0b00010000,
+	0b00000100, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001000, 0b00000000, 0b00000000, 0b00010000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	// Mask
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000001, 0b11111111, 0b11111111, 0b11110000,
+	0b00000011, 0b11111111, 0b11111111, 0b11110000,
+	0b00000111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00000011, 0b11111111, 0b11111111, 0b11110000,
+	0b00000011, 0b11111111, 0b11111111, 0b11110000,
+	0b00000011, 0b11111111, 0b11111111, 0b11110000,
+	0b00000111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00001111, 0b11111111, 0b11111111, 0b11110000,
+	0b00000000, 0b00000000, 0b00000000, 0b00000000,
+	25, 'G', 'a', 'r', 'r', 'e', 't', 't', '\'', 's', ' ', 
+	'W', 'o', 'r', 'k', 's', 'h', 'o', 'p', ' ', 
+	'R', 'O', 'M', 'B', 'U', 'S', 0
+};
+
+#endif
\ No newline at end of file
diff --git a/sdmmc.c b/sdmmc.c
new file mode 100644
index 0000000..048f678
--- /dev/null
+++ b/sdmmc.c
@@ -0,0 +1,220 @@
+#include "sdmmc.h"
+
+
+/*--------------------------------------------------------------------------
+
+   Module Private Functions
+
+---------------------------------------------------------------------------*/
+
+#define	INIT_PORT()	init_port()	/* Initialize MMC control port (CS/CLK/DI:output, DO:input) */
+#define DLY_US(n)	dly_us(n)	/* Delay n microseconds */
+#define	FORWARD(d)	forward(d)	/* Data in-time processing function (depends on the project) */
+
+/* Definitions for MMC/SDC command */
+#define CMD0	(0x40+0)	/* GO_IDLE_STATE */
+#define CMD1	(0x40+1)	/* SEND_OP_COND (MMC) */
+#define	ACMD41	(0xC0+41)	/* SEND_OP_COND (SDC) */
+#define CMD8	(0x40+8)	/* SEND_IF_COND */
+#define CMD16	(0x40+16)	/* SET_BLOCKLEN */
+#define CMD17	(0x40+17)	/* READ_SINGLE_BLOCK */
+#define CMD24	(0x40+24)	/* WRITE_BLOCK */
+#define CMD55	(0x40+55)	/* APP_CMD */
+#define CMD58	(0x40+58)	/* READ_OCR */
+
+/* Card type flags (CardType) */
+#define CT_MMC				0x01	/* MMC ver 3 */
+#define CT_SD1				0x02	/* SD ver 1 */
+#define CT_SD2				0x04	/* SD ver 2 */
+#define CT_SDC				(CT_SD1|CT_SD2)	/* SD */
+#define CT_BLOCK			0x08	/* Block addressing */
+
+
+
+static char CardType;			/* 0:MMC, 1:SDv1, 2:SDv2, 3:Block addressing */
+
+
+/*-----------------------------------------------------------------------*/
+/* Send a command packet to MMC                                          */
+/*-----------------------------------------------------------------------*/
+static char send_cmd(char cmd, long arg)
+{
+	char n, res;
+
+	if (cmd & 0x80) {	/* ACMD<n> is the command sequense of CMD55-CMD<n> */
+		cmd &= 0x7F;
+		res = send_cmd(CMD55, 0);
+		if (res > 1) return res;
+	}
+
+	/* Select the card */
+	CS_H(); spi_rx();
+	CS_L(); spi_rx();
+
+	/* Send a command packet */
+	spi_tx(cmd);					/* Start + Command index */
+	s((BYTE)(arg >> 24));	/* Argument[31..24] */
+	spi_tx((BYTE)(arg >> 16));	/* Argument[23..16] */
+	spi_tx((BYTE)(arg >> 8));		/* Argument[15..8] */
+	spi_tx((BYTE)arg);			/* Argument[7..0] */
+	n = 0x01;						/* Dummy CRC + Stop */
+	if (cmd == CMD0) n = 0x95;		/* Valid CRC for CMD0(0) */
+	if (cmd == CMD8) n = 0x87;		/* Valid CRC for CMD8(0x1AA) */
+	spi_tx(n);
+
+	/* Receive a command response */
+	n = 10;								/* Wait for a valid response in timeout of 10 attempts */
+	do {
+		res = spi_rx();
+	} while ((res & 0x80) && --n);
+
+	return res;			/* Return with the response value */
+}
+
+
+
+/*--------------------------------------------------------------------------
+
+   Public Functions
+
+---------------------------------------------------------------------------*/
+
+
+/*-----------------------------------------------------------------------*/
+/* Initialize Disk Drive                                                 */
+/*-----------------------------------------------------------------------*/
+sdstatus_t sdmmc_init()
+{
+	char n, cmd, ty, buf[4];
+	uint tmr;
+
+	CS_H();
+	spi_skip(10);			/* Dummy clocks */
+
+	ty = 0;
+	if (send_cmd(CMD0, 0) == 1) {			/* Enter Idle state */
+		if (send_cmd(CMD8, 0x1AA) == 1) {	/* SDv2 */
+			for (n = 0; n < 4; n++) buf[n] = spi_rx();	/* Get trailing return value of R7 resp */
+			if (buf[2] == 0x01 && buf[3] == 0xAA) {			/* The card can work at vdd range of 2.7-3.6V */
+				for (tmr = 1000; tmr; tmr--) {				/* Wait for leaving idle state (ACMD41 with HCS bit) */
+					if (send_cmd(ACMD41, 1UL << 30) == 0) break;
+					DLY_US(1000);
+				}
+				if (tmr && send_cmd(CMD58, 0) == 0) {		/* Check CCS bit in the OCR */
+					for (n = 0; n < 4; n++) buf[n] = spi_rx();
+					ty = (buf[0] & 0x40) ? CT_SD2 | CT_BLOCK : CT_SD2;	/* SDv2 (HC or SC) */
+				}
+			}
+		} else {							/* SDv1 or MMCv3 */
+			if (send_cmd(ACMD41, 0) <= 1) 	{
+				ty = CT_SD1; cmd = ACMD41;	/* SDv1 */
+			} else {
+				ty = CT_MMC; cmd = CMD1;	/* MMCv3 */
+			}
+			for (tmr = 1000; tmr; tmr--) {			/* Wait for leaving idle state */
+				if (send_cmd(cmd, 0) == 0) break;
+				DLY_US(1000);
+			}
+			if (!tmr || send_cmd(CMD16, 512) != 0)			/* Set R/W block length to 512 */
+				ty = 0;
+		}
+	}
+	CardType = ty;
+	release_spi();
+
+	return ty ? 0 : STA_NOINIT;
+}
+
+
+/*-----------------------------------------------------------------------*/
+/* Read partial sector                                                   */
+/*-----------------------------------------------------------------------*/
+sdresult_t sdmmc_readp(Ptr buf, long sector, uint offset, uint count)
+{
+	DRESULT res;
+	char d;
+	uint bc, tmr;
+
+
+	if (!(CardType & CT_BLOCK)) sector *= 512;	/* Convert to byte address if needed */
+
+	res = RES_ERROR;
+	if (send_cmd(CMD17, sector) == 0) {		/* READ_SINGLE_BLOCK */
+
+		tmr = 1000;
+		do {							/* Wait for data packet in timeout of 100ms */
+			DLY_US(100);
+			d = spi_rx();
+		} while (d == 0xFF && --tmr);
+
+		if (d == 0xFE) {				/* A data packet arrived */
+			bc = 514 - offset - count;
+
+			/* Skip leading bytes */
+			if (offset) spi_skip(offset);
+
+			/* Receive a part of the sector */
+			if (buff) {	/* Store data to the memory */
+				do
+					*buff++ = spi_rx();
+				while (--count);
+			} else {	/* Forward data to the outgoing stream */
+				do {
+					d = spi_rx();
+					FORWARD(d);
+				} while (--count);
+			}
+
+			/* Skip trailing bytes and CRC */
+			spi_skip(bc);
+
+			res = RES_OK;
+		}
+	}
+
+	release_spi();
+
+	return res;
+}
+
+
+/*-----------------------------------------------------------------------*/
+/* Write partial sector                                                  */
+/*-----------------------------------------------------------------------*/
+sdresult_t sdmmc_writep(const Ptr buf, long sc)
+{
+	DRESULT res;
+	UINT bc, tmr;
+	static UINT wc;
+
+	res = RES_ERROR;
+
+	if (buff) {		/* Send data bytes */
+		bc = (UINT)sc;
+		while (bc && wc) {		/* Send data bytes to the card */
+			spi_tx(*buff++);
+			wc--; bc--;
+		}
+		res = RES_OK;
+	} else {
+		if (sc) {	/* Initiate sector write transaction */
+			if (!(CardType & CT_BLOCK)) sc *= 512;	/* Convert to byte address if needed */
+			if (send_cmd(CMD24, sc) == 0) {			/* WRITE_SINGLE_BLOCK */
+				spi_tx(0xFF); spi_tx(0xFE);		/* Data block header */
+				wc = 512;							/* Set byte counter */
+				res = RES_OK;
+			}
+		} else {	/* Finalize sector write transaction */
+			bc = wc + 2;
+			while (bc--) spi_tx(0);	/* Fill left bytes and CRC with zeros */
+			if ((spi_rx() & 0x1F) == 0x05) {	/* Receive data resp and wait for end of write process in timeout of 300ms */
+				for (tmr = 10000; spi_rx() != 0xFF && tmr; tmr--)	/* Wait for ready (max 1000ms) */
+					DLY_US(100);
+				if (tmr) res = RES_OK;
+			}
+			release_spi();
+		}
+	}
+
+	return res;
+}
diff --git a/sdmmc.h b/sdmmc.h
new file mode 100644
index 0000000..e2a49b6
--- /dev/null
+++ b/sdmmc.h
@@ -0,0 +1,29 @@
+#ifndef SDMMC_H
+#define SDMMC_H
+
+
+/* Status of Disk Functions */
+typedef char sdstatus_t;
+
+#define STA_NOINIT		0x01	/* Drive not initialized */
+#define STA_NODISK		0x02	/* No medium in the drive */
+
+
+/* Results of Disk Functions */
+typedef enum sdmmc_result_e {
+	RES_OK = 0,		/* 0: Function succeeded */
+	RES_ERROR,		/* 1: Disk error */
+	RES_NOTRDY,		/* 2: Not ready */
+	RES_PARERR		/* 3: Invalid parameter */
+} sdresult_t;
+
+
+/*---------------------------------------*/
+/* Prototypes for disk control functions */
+/*---------------------------------------*/
+sdstatus_t sdmmc_init();
+sdresult_t sdmmc_readp(Ptr buf, long sector, uint offset, uint count);
+sdresult_t sdmmc_writep(const Ptr buf, long sc);
+
+
+#endif
diff --git a/spi.c b/spi.c
new file mode 100644
index 0000000..4b918ff
--- /dev/null
+++ b/spi.c
@@ -0,0 +1,164 @@
+#include "spi.h"
+
+/*-------------------------------------------------------------------------*/
+/* Platform dependent macros and functions needed to be modified           */
+/*-------------------------------------------------------------------------*/
+#define	CS_H()		bset(P0)	/* Set MMC CS "high" */
+#define CS_L()		bclr(P0)	/* Set MMC CS "low" */
+#define CK_H()		bset(P1)	/* Set MMC SCLK "high" */
+#define	CK_L()		bclr(P1)	/* Set MMC SCLK "low" */
+#define DI_H()		bset(P2)	/* Set MMC DI "high" */
+#define DI_L()		bclr(P2)	/* Set MMC DI "low" */
+#define DO			btest(P3)	/* Test MMC DO (high:true, low:false) */
+
+
+// Command listing
+/* T16: Transfer 16-bit
+ * First, the 16-bit value encoded in the address bits A[17:2] is latched.
+ * The data output mux is set to the current RXR and the cycle completes.
+ * Shortly after /AS rises, the SPI transfer engine begins
+ * transferring the latched value.
+ */
+/* T16S: Transfer 16-bit Swapped
+ * Same as T16L but read data is byte-swapped.
+ */
+/* MERT: Measure Elapsed time and Reset Timer
+ * The elapsed time since the last MERT command is returned in D[31:24]
+ * and the timer is reset.
+ */
+/* SKIP1: Skip Clocks with MOSI "1"
+ * 
+ */
+/* SKIP0: Skip Clocks with MOSI "0"
+ *
+ */
+/* T8S: Transfer 8-bit Swapped
+ * Same as T8 but read data is byte-swapped.
+ */
+/* T8: Transfer 8-bit
+ * First, the 8-bit value encoded in the address bits A[9:2] is latched.
+ * The data output mux is set to the current RXR and the cycle completes.
+ * Shortly after /AS rises, the SPI transfer engine begins
+ * transferring the latched value.
+ */
+/* WRC: Write Command
+ * The command encoded in address bits A[9:2] is sent to the command target
+ * corresponding to the address bits A[15:10].
+ * Command targets:
+ *	$00 - Set bitbang
+ *			A[2] - SCS value
+ */
+/* RDRXR: Read Receive Data Register
+ * The the current RXR is returned in D[31:16] and the cycle completes.
+ */
+/* RDRXRS: Read Receive Data Register Swapped
+ * Same as RDRXR but read data is byte-swapped.
+ */
+/* MAGIC: Write Command
+ * Write sequence $FF $00 $55 $AA $C1 $AD
+ * to enable registers at $40890000-$4097FFFF.
+ * Write anything else to disable them.
+ * Always reads 0xC1AD
+ */
+
+// SPI controller address map:
+// 40940000-4097FFFF (256 kB, D[31:16]) T16S. Write transfer data in A[17:2].
+// 40900000-4093FFFF (256 kB, D[31:16]) T16. Write transfer data in A[17:2].
+// 408C0000-408FFFFF (320 kB) reserved
+// 408A0000-408AFFFF ( 64 kB, D[31:24]) WRC. Write port address in A[15:10] and data in A[9:2].
+// 40891C00-4089FFFF ( 55 kB) reserved
+// 40892000-408923FF (  1 kB, D[31:24]) MERT.
+// 40891C00-40891FFF (  1 kB) SKIP1. Write bytes to skip in A[9:2].
+// 40891800-40891BFF (  1 kB) SKIP0. Write bytes to skip in A[9:2].
+// 40891400-408917FF (  1 kB, D[31:16]) T8S. Write transfer data in A[9:2].
+// 40891000-408913FF (  1 kB, D[31:16]) T8. Write transfer data in A[9:2].
+// 40890C00-40890FFF (  1 kB, D[31:16]) RDRXRS.
+// 40890800-40890BFF (  1 kB, D[31:16]) RDRXR.
+// 40890400-408907FF (  1 kB) reserved
+// 40890000-408903FF (  1 kB, D[31:24]) MAGIC. Write magic numbers in A[9:2].
+// 40880000-408FFFFF ( 64 kB, D[31:00]) ROMBUS driver data
+
+#define RB_T16S(x)		(*(volatile int*)	(0x40940000 + ((x && 0xFFFF)<<02)) )
+#define RB_T16(x)		(*(volatile int*)	(0x40900000 + ((x && 0xFFFF)<<02)) )
+#define RB_RDS(a)		(*(volatile char*)	(0x408B0000 + ((a && 0x003F)<<10)) )
+#define RB_WRC(a,d)		(*(volatile char*)	(0x408A0000 + ((a && 0x003F)<<10) 
+														+ ((d && 0x00FF)<<02)) )
+#define RB_MERT(x)		(*(volatile char*)	(0x40892000 + ((x && 0xFFFF)<<02)) )
+#define RB_SKIP1(n)		(*(volatile char*)	(0x40891C00 + ((x && 0xFFFF)<<02)) )
+#define RB_SKIP0(n)		(*(volatile char*)	(0x40891800 + ((x && 0xFFFF)<<02)) )
+#define RB_T8S(x)		(*(volatile int*)	(0x40891400 + ((x && 0xFFFF)<<02)) )
+#define RB_T8(x)		(*(volatile int*)	(0x40891000 + ((x && 0xFFFF)<<02)) )
+#define RB_RDRXRS		(*(volatile int*)	(0x40890C00 + ((x && 0xFFFF)<<02)) )
+#define RB_RDRXR		(*(volatile int*)	(0x40890800 + ((x && 0xFFFF)<<02)) )
+#define RB_WRMOSI(x)	(*(volatile char*)	(0x40890400 + ((x && 0x0001)<<02)) )
+#define RB_MAGIC(x)		(*(volatile char*)	(0x40890000 + ((x && 0xFFFF)<<02)) )
+
+#define SPI_GET_MISO(d)	(d & 1)
+
+void spi_select() { 
+	ret = *SPI_CMD_SEL0;
+	ret = *SPI_CMD_SEL1;
+	ret = *SPI_CMD_SEL2;
+	ret = *SPI_CMD_SEL3;
+}
+void spi_deselect() {
+	ret = *SPI_CMD_DES0;
+	ret = *SPI_CMD_DES1;
+	ret = *SPI_CMD_DES2;
+	ret = *SPI_CMD_DES3;
+}
+
+void spi_tx_slow(char d) {
+	for (int i = 0; i < 8; i++) {
+		*SPI_CMD_BBA((0 & 0x02) | (d & 0x01));
+		*SPI_CMD_BBA((1 & 0x02) | (d & 0x01));
+		d >>= 1;
+	}
+	*SPI_CMD_BBA((0 & 0x02) | (0 & 0x01));
+}
+
+char spi_rx_slow() {
+	char ret = 0;
+	for (int i = 0; i < 8; i++) {
+		*SPI_CMD_BBA((0 & 0x02) | (1 & 0x01));
+		*SPI_CMD_BBA((1 & 0x02) | (1 & 0x01));
+		ret = (ret << 1) + (*SPI_CMD_BBA((1 & 0x02) | (1 & 0x01)) & 1);
+	}
+	return ret;
+}
+
+void spi_skip_slow(int n) {
+	while (n-- > 0) {
+		for (int i = 0; i < 8; i++) {
+			*SPI_CMD_BBA((0 & 0x02) | (1 & 0x01));
+			*SPI_CMD_BBA((1 & 0x02) | (1 & 0x01));
+		}
+	}
+	*SPI_CMD_BBA((0 & 0x02) | (1 & 0x01));
+}
+
+void spi_tx_8(char d) {
+	*SPI_CMD_SH8(d);
+}
+
+char spi_rx_8() {
+	*SPI_CMD_SH8(0xFF);
+	return *SPI_CMD_RD & 0xFF;
+}
+
+void spi_tx_16(int d) {
+	*SPI_CMD_SH16(d);
+}
+
+int spi_rx_16() {
+	*SPI_CMD_SH16(0xFFFF);
+	return *SPI_CMD_RD & 0xFFFF;
+}
+
+void spi_skip(int n) {
+	while (n-- > 0) {
+		for (int i = 0; i < 8; i++) {
+			*SPI_CMD_SH8(0xFF);
+		}
+	}
+}
diff --git a/spi.h b/spi.h
new file mode 100644
index 0000000..70ee2c5
--- /dev/null
+++ b/spi.h
@@ -0,0 +1,17 @@
+#ifndef SPI_H
+#define SPI_H
+
+void spi_select();
+void spi_deselect();
+
+void spi_tx_slow(char d);
+char spi_rx_slow();
+void spi_skip_slow(int n);
+
+void spi_tx_8(char d);
+char spi_rx_8();
+void spi_tx_16(int d);
+int spi_rx_16();
+void spi_skip(int n);
+
+#endif
diff --git a/xfer.h b/xfer.h
new file mode 100644
index 0000000..bc81450
--- /dev/null
+++ b/xfer.h
@@ -0,0 +1,11 @@
+#ifndef RDISK_H
+#define RDISK_H
+
+#pragma parameter xfer_s_256(__A0, __A1)
+void xfer_s_256(Ptr srcreg, Ptr destmem);
+
+#pragma parameter xfer_s(__D0, __A0, __A1)
+void xfer_s(uint8_t numBytes, Ptr srcreg, Ptr destmem);
+
+
+#endif
diff --git a/xfer.s b/xfer.s
new file mode 100644
index 0000000..2c9b1d6
--- /dev/null
+++ b/xfer.s
@@ -0,0 +1,34 @@
+	.macro  	xfer_in	from, to
+	move.w		(%A0), (%A1)+
+	nop
+	nop
+	nop
+	.if			\to-\from
+	xfer_in	"(\from+1)"
+	.else
+	
+	.endif
+	.endm
+
+
+;pragma parameter xfer_s_256(__A0, __A1)
+;void xfer_s_256(Ptr srcreg, Ptr destmem);
+xfer_256:
+	movem.l		%D0/%A1-%A2, -(%SP)
+xfer_256_loop:
+	xfer_s_in	0, 255
+xfer_256_end:
+	movem.l		(%SP)+, %D0/%A1-%A2
+
+
+;pragma parameter xfer_s(__D0, __A0, __A1)
+;void xfer_s(uint8_t numBytes, Ptr srcreg, Ptr destmem);
+xfer:
+	movem.l		%D0/%A1-%A2, -(%SP)
+	andi.l 		#0xFF, %D0
+	subi.l 		#256, %D0
+	neg.l 		%D0
+	lsl.l 		#2, %D0
+	addi.l 		#xfer_256, %D0
+	movea.l 	%D0, %A2
+	jmp 		%A2