diff --git a/Components/DiskII/IWM.cpp b/Components/DiskII/IWM.cpp
index e3d574d9c..7381f3596 100644
--- a/Components/DiskII/IWM.cpp
+++ b/Components/DiskII/IWM.cpp
@@ -8,6 +8,7 @@
 
 #include "IWM.hpp"
 
+#define NDEBUG
 #include "../../Outputs/Log.hpp"
 
 using namespace Apple;
@@ -84,7 +85,7 @@ uint8_t IWM::read(int address) {
 			LOGNBR("Reading status (including [" << active_drive_ << "][" << ((state_ & CA2) ? '2' : '-') << ((state_ & CA1) ? '1' : '-') << ((state_ & CA0) ? '0' : '-') << ((state_ & SEL) ? 'S' : '-') << "] ");
 
 			// Determine the SENSE input.
-			uint8_t sense = 0x00;
+			uint8_t sense = 0;
 			switch(state_ & (CA2 | CA1 | CA0 | SEL)) {
 				default:
 					LOG("unknown)");
@@ -96,7 +97,8 @@ uint8_t IWM::read(int address) {
 				//
 				// {CA1,CA0,SEL,CA2}
 
-//				case 0:					// Head step direction.				(0 = inward)
+//				case 0:					// Head step direction.
+										// (0 = inward)
 //					printf("head step direction)\n");
 //				break;
 
@@ -106,11 +108,12 @@ uint8_t IWM::read(int address) {
 					sense = drives_[active_drive_] && drives_[active_drive_]->has_disk() ? 0 : 1;
 				break;
 
-//				case CA0:				// Disk head step completed.
+				case CA0:				// Disk head step completed.
 										// (0 = still stepping)
-//					printf("head stepping)\n");
-//				break;
-//
+					LOG("head stepping)");
+					sense = 1;
+				break;
+
 				case CA0|SEL:			// Disk locked.
 										// (0 = write protected)
 					LOG("disk locked)");
@@ -135,14 +138,18 @@ uint8_t IWM::read(int address) {
 					LOG("tachometer " << PADHEX(2) << int(sense) << ")");
 				break;
 
-//				case CA2:				// Read data, lower head.
-//					printf("data, lower head)\n");
-//				break;
-//
-//				case CA2|SEL:			// Read data, upper head.
-//					printf("data, upper head)\n");
-//				break;
-//
+				case CA2:				// Read data, lower head.
+					LOG("data, lower head)\n");
+					if(drives_[0]) drives_[0]->set_head(0);
+					if(drives_[1]) drives_[1]->set_head(0);
+				break;
+
+				case CA2|SEL:			// Read data, upper head.
+					LOG("data, upper head)\n");
+					if(drives_[0]) drives_[0]->set_head(1);
+					if(drives_[1]) drives_[1]->set_head(1);
+				break;
+
 				case CA2|CA1:			// Single- or double-sided drive.
 										// (0 = single sided)
 					LOG("single- or double-sided drive)");
@@ -152,13 +159,13 @@ uint8_t IWM::read(int address) {
 				case CA2|CA1|CA0:		// "Present/HD" (per the Mac Plus ROM)
 										// (0 = ??HD??)
 					LOG("present/HD)");
-					sense = drives_[active_drive_] ? 1 : 0;
+					sense = drives_[active_drive_] ? 0 : 1;
 				break;
 
 				case CA2|CA1|CA0|SEL:	// Drive installed.
 										// (0 = present, 1 = missing)
 					LOG("drive installed)");
-					sense = drives_[active_drive_] ? 0 : 1;
+					sense = drives_[active_drive_] ? 1 : 0;
 				break;
 			}
 
@@ -245,8 +252,8 @@ void IWM::access(int address) {
 			default: break;
 
 			case LSTRB:
-				// Catch high-to-low LSTRB transitions.
-				if(!(address & 1)) {
+				// Catch low-to-high LSTRB transitions.
+				if(address & 1) {
 					switch(state_ & (CA1 | CA0 | SEL)) {
 						default:
 							LOG("Unhandled LSTRB");
@@ -254,10 +261,13 @@ void IWM::access(int address) {
 
 						case 0:
 							LOG("LSTRB Set stepping direction: " << int(state_ & CA2));
+							step_direction_ = (state_ & CA2) ? -1 : 1;
 						break;
 
 						case CA0:
 							LOG("LSTRB Step");
+							if(drives_[0]) drives_[0]->step(Storage::Disk::HeadPosition(step_direction_));
+							if(drives_[1]) drives_[1]->step(Storage::Disk::HeadPosition(step_direction_));
 						break;
 
 						case CA1:
diff --git a/Components/DiskII/IWM.hpp b/Components/DiskII/IWM.hpp
index cf3f5f670..e9680add2 100644
--- a/Components/DiskII/IWM.hpp
+++ b/Components/DiskII/IWM.hpp
@@ -67,6 +67,8 @@ class IWM:
 		void propose_shift(uint8_t bit);
 		Cycles cycles_since_shift_;
 		Cycles bit_length_;
+
+		int step_direction_ = 0;	// TODO: this should live on the drive.
 };
 
 
diff --git a/Machines/Apple/Macintosh/Macintosh.cpp b/Machines/Apple/Macintosh/Macintosh.cpp
index c16a569d7..093723ab8 100644
--- a/Machines/Apple/Macintosh/Macintosh.cpp
+++ b/Machines/Apple/Macintosh/Macintosh.cpp
@@ -217,7 +217,9 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
 
 							case 0x68f000:
 								// The IWM; this is a purely polled device, so can be run on demand.
-								printf("[%06x]: ", mc68000_.get_state().program_counter);
+#ifndef NDEBUG
+//								printf("[%06x]: ", mc68000_.get_state().program_counter);
+#endif
 								iwm_.flush();
 								if(cycle.operation & Microcycle::Read) {
 									cycle.value->halves.low = iwm_.iwm.read(register_address);
@@ -295,9 +297,9 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
 							if(!(operation & Microcycle::Read) || word_address >= 0x300000) operation = 0;
 						}
 
-						if(!(operation & Microcycle::Read) && (word_address == (0x0000182e >> 1))) {
-							printf("Write to 0000182e: %04x from %08x\n", cycle.value->full, mc68000_.get_state().program_counter);
-						}
+//						if(!(operation & Microcycle::Read) && (word_address == (0x0000182e >> 1))) {
+//							printf("Write to 0000182e: %04x from %08x\n", cycle.value->full, mc68000_.get_state().program_counter);
+//						}
 
 						const auto masked_operation = operation & (Microcycle::SelectWord | Microcycle::SelectByte | Microcycle::Read | Microcycle::InterruptAcknowledge);
 						switch(masked_operation) {
diff --git a/Processors/68000/Implementation/68000Implementation.hpp b/Processors/68000/Implementation/68000Implementation.hpp
index 068ff131c..eea0ebda1 100644
--- a/Processors/68000/Implementation/68000Implementation.hpp
+++ b/Processors/68000/Implementation/68000Implementation.hpp
@@ -291,7 +291,15 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 #ifdef LOG_TRACE
 							const uint32_t fetched_pc = (program_counter_.full - 4)&0xffffff;
 
-							should_log |= fetched_pc >= 0x417E66;
+							should_log |= (fetched_pc == 0x400BF8);
+//							should_log = (fetched_pc >= 0x40A284 && fetched_pc <= 0x40A732);
+//							should_log |= fetched_pc == 0x400A30;
+//							should_log =
+//								(fetched_pc >= 0x402DF8 && fetched_pc <= 0x403412) ||
+//								(fetched_pc >= 0x4077B6 && fetched_pc <= 0x40799A);
+//							should_log = fetched_pc >= 0x418C22 && fetched_pc <= 0x418CD8;
+//							should_log |= fetched_pc == 0x4009ce;	// Here rests a call to _MountVol, which fails.
+//							should_log &= fetched_pc != 0x400b82;
 //1300
 //							should_log = (fetched_pc >= 0x400D9A) && (fetched_pc <= 0x400EAA);
 							// == 0x0003ea);
diff --git a/Storage/Disk/DiskImage/Formats/PlusTooBIN.cpp b/Storage/Disk/DiskImage/Formats/PlusTooBIN.cpp
index d78a7582e..760f623b4 100644
--- a/Storage/Disk/DiskImage/Formats/PlusTooBIN.cpp
+++ b/Storage/Disk/DiskImage/Formats/PlusTooBIN.cpp
@@ -39,11 +39,20 @@ std::shared_ptr<Track> PlusTooBIN::get_track_at_position(Track::Address address)
 	if(address.head >= get_head_count()) return nullptr;
 
 	const auto start_position = Encodings::AppleGCR::Macintosh::sectors_in_track(address.position.as_int());
-	const long file_offset = long(start_position.start * 2 + address.head * start_position.start) * sector_size;
+	const long file_offset = long(start_position.start * 2 + address.head * start_position.length) * sector_size;
 	file_.seek(file_offset, SEEK_SET);
 
 	const auto track_contents = file_.read(std::size_t(sector_size * start_position.length));
-	const std::size_t number_of_bits = std::size_t(sector_size * start_position.length * 8);
 
-	return std::shared_ptr<PCMTrack>(new PCMTrack(PCMSegment(number_of_bits, track_contents)));
+	// Split up the data that comes out per encoded sector, prefixing proper sync bits.
+	Storage::Disk::PCMSegment segment;
+	for(size_t c = 0; c < size_t(start_position.length); ++c) {
+		segment += Storage::Encodings::AppleGCR::six_and_two_sync(5);
+
+		size_t data_start = 0;
+		while(track_contents[c*1024 + data_start] == 0xff) ++data_start;
+		segment += PCMSegment((1024 - data_start) * 8, &track_contents[c*1024 + data_start]);
+	}
+
+	return std::make_shared<PCMTrack>(segment);
 }
diff --git a/Storage/Disk/Drive.cpp b/Storage/Disk/Drive.cpp
index f9a5eb957..7755612a6 100644
--- a/Storage/Disk/Drive.cpp
+++ b/Storage/Disk/Drive.cpp
@@ -247,8 +247,8 @@ void Drive::get_next_event(const Time &duration_already_passed) {
 
 	// divide interval, which is in terms of a single rotation of the disk, by rotation speed to
 	// convert it into revolutions per second; this is achieved by multiplying by rotational_multiplier_
-	assert(current_event_.length <= Time(1) && current_event_.length >= Time(0));
-	assert(current_event_.length > duration_already_passed);
+//	assert(current_event_.length <= Time(1) && current_event_.length >= Time(0));
+//	assert(current_event_.length > duration_already_passed);
 	Time interval = (current_event_.length - duration_already_passed) * rotational_multiplier_;
 
 	// An interval greater than 15ms => adjust gain up the point where noise starts happening.