diff --git a/presets/nes/ex0.asm b/presets/nes/ex0.asm
index b5020e42..26a90ce2 100644
--- a/presets/nes/ex0.asm
+++ b/presets/nes/ex0.asm
@@ -13,17 +13,19 @@
 ;;;;; START OF CODE
 
 Start:
+; wait for PPU warmup; clear CPU RAM
 	NES_INIT	; set up stack pointer, turn off PPU
         jsr WaitSync	; wait for VSYNC
         jsr ClearRAM	; clear RAM
         jsr WaitSync	; wait for VSYNC (and PPU warmup)
-
+; set palette
 	lda #$3f	; $3F -> A register
         sta PPU_ADDR	; write high byte first
 	lda #$00	; $00 -> A register
         sta PPU_ADDR    ; $3F00 -> PPU address
         lda #$1c	; $1C = light blue color
         sta PPU_DATA    ; $1C -> PPU data
+; activate PPU graphics
         lda #CTRL_NMI
         sta PPU_CTRL	; enable NMI
         lda #MASK_COLOR
diff --git a/presets/nes/ex1.asm b/presets/nes/ex1.asm
index 42574a67..678bd8a0 100644
--- a/presets/nes/ex1.asm
+++ b/presets/nes/ex1.asm
@@ -13,17 +13,21 @@
 ;;;;; START OF CODE
 
 Start:
+; wait for PPU warmup; clear CPU RAM
 	NES_INIT	; set up stack pointer, turn off PPU
         jsr WaitSync	; wait for VSYNC
         jsr ClearRAM	; clear RAM
         jsr WaitSync	; wait for VSYNC (and PPU warmup)
+; set palette and nametable VRAM
 	jsr SetPalette	; set palette colors
-        jsr HelloVRAM	; set PPU video RAM
+        jsr HelloVRAM	; print message in name table
+; reset PPU address and scroll registers
         lda #0
         sta PPU_ADDR
         sta PPU_ADDR	; PPU addr = $0000
         sta PPU_SCROLL
-        sta PPU_SCROLL  ; scroll = $0000
+        sta PPU_SCROLL  ; PPU scroll = $0000
+; activate PPU graphics
         lda #CTRL_NMI
         sta PPU_CTRL	; enable NMI
         lda #MASK_BG
@@ -88,4 +92,3 @@ Palette:
 
 	org $10000
         incbin "jroatch.chr"
-
diff --git a/presets/nes/ex2.asm b/presets/nes/ex2.asm
index f44c5806..381d90a4 100644
--- a/presets/nes/ex2.asm
+++ b/presets/nes/ex2.asm
@@ -15,18 +15,21 @@ ScrollPos	word	; used during NMI
 ;;;;; START OF CODE
 
 Start:
+; wait for PPU warmup; clear CPU RAM
 	NES_INIT	; set up stack pointer, turn off PPU
         jsr WaitSync	; wait for VSYNC
         jsr ClearRAM	; clear RAM
         jsr WaitSync	; wait for VSYNC (and PPU warmup)
-
+; set palette and nametable VRAM
 	jsr SetPalette	; set palette colors
         jsr FillVRAM	; set PPU video RAM
+; reset PPU address and scroll registers
         lda #0
         sta PPU_ADDR
         sta PPU_ADDR	; PPU addr = $0000
         sta PPU_SCROLL
         sta PPU_SCROLL  ; scroll = $0000
+; activate PPU graphics
         lda #CTRL_NMI
         sta PPU_CTRL	; enable NMI
         lda #MASK_BG
@@ -41,7 +44,7 @@ FillVRAM: subroutine
 .loop:
 	tya		; Y -> A
         ora #$40	; A = A OR $40
-	sta PPU_DATA	; X -> PPU data port
+	sta PPU_DATA	; A -> PPU data port
 	inx		; X = X + 1
 	bne .loop	; repeat until 256 bytes
 	dey		; Y = Y - 1
diff --git a/presets/nes/ex3.asm b/presets/nes/ex3.asm
index bb83c58f..6f39e107 100644
--- a/presets/nes/ex3.asm
+++ b/presets/nes/ex3.asm
@@ -43,55 +43,53 @@ Start:
 
 ; fill video RAM
 FillVRAM: subroutine
-	PPU_SETADDR	$2000
+	PPU_SETADDR $2000
 	ldy #$10
 .loop:
-	stx PPU_DATA
-	inx
-	bne .loop
-	dey
-	bne .loop
-        rts
+	stx PPU_DATA	; X -> PPU data port
+	inx		; X = X + 1
+	bne .loop	; repeat until 256 bytes
+	dey		; Y = Y - 1
+	bne .loop	; repeat until Y is 0
+        rts		; return to caller
 
-;
+; initialize OAM data
 InitSprites: subroutine
-	lda #1
-        ldx #0
+	lda #1		; A = 1
+        ldx #0		; X = 0
 .loop
-	sta SpriteBuf,x
-        jsr NextRandom
-        inx
-        bne .loop
-        rts
+	sta SpriteBuf,x	; store to OAM buffer
+        jsr NextRandom	; get next random number
+        inx		; X = X + 1
+        bne .loop	; loop until X wraps
+        rts		; return to caller
 
-;
+; move sprite data
 MoveSprites: subroutine
-	lda #1
-        ldx #0
+	lda #1		; A = 1
+        ldx #0		; X = 0
 .loop
-	sta Temp1
-        and #3
-        clc
-        adc SpriteBuf,x
-	sta SpriteBuf,x
-        lda Temp1
-        jsr NextRandom
-        inx
-        bne .loop
-        rts
+	sta Temp1	; save A
+        and #3		; keep lower 2 bits
+        clc		; clear carry before add
+        adc SpriteBuf,x	; add to sprite buffer
+	sta SpriteBuf,x ; store in sprite buffer
+        lda Temp1	; restore A
+        jsr NextRandom	; get next random number
+        inx		; X = X + 1
+        bne .loop	; loop until X wraps
+        rts		; return to caller
 
 ; set palette colors
-
 SetPalette: subroutine
-	PPU_SETADDR	$3f00
-	ldx #32
+	PPU_SETADDR $3f00
 .loop:
-	lda Palette,y
-	sta PPU_DATA
-        iny
-	dex
-	bne .loop
-        rts
+	lda Palette,y	; lookup byte in ROM
+	sta PPU_DATA	; store byte to PPU data
+        iny		; Y = Y + 1
+        cpy #32		; is Y equal to 32?
+	bne .loop	; not yet, loop
+        rts		; return to caller
 
 
 ;;;;; COMMON SUBROUTINES
diff --git a/src/platform/nes.ts b/src/platform/nes.ts
index aa494da1..c8de1348 100644
--- a/src/platform/nes.ts
+++ b/src/platform/nes.ts
@@ -80,13 +80,13 @@ const _JSNESPlatform = function(mainElement) {
   var frameindex = 0;
   var ntvideo;
   var ntlastbuf;
-  
+
  class JSNESPlatform extends Base6502Platform implements Platform {
 
   getPresets() { return JSNES_PRESETS; }
 
   start() {
-    var self = this;
+    this.debugPCDelta = 1;
     var debugbar = $("<div>").appendTo(mainElement);
     audio = new SampleAudio(audioFrequency);
     video = new RasterVideo(mainElement,256,224,{overscan:true});
@@ -99,7 +99,7 @@ const _JSNESPlatform = function(mainElement) {
     // toggle buttons
     $('<button>').text("Video").appendTo(debugbar).click(() => { $(video.canvas).toggle() });
     $('<button>').text("Nametable").appendTo(debugbar).click(() => { $(ntvideo.canvas).toggle() });
-    
+
     var idata = video.getFrameData();
     nes = new jsnes.NES({
       onFrame: (frameBuffer : number[]) => {
@@ -121,31 +121,31 @@ const _JSNESPlatform = function(mainElement) {
       //TODO: onBatteryRamWrite
     });
     //nes.ppu.clipToTvSize = false;
-    nes.stop = function() {
+    nes.stop = () => {
       // TODO: trigger breakpoint
-      self.pause();
+      this.pause();
       console.log(nes.cpu.toJSON());
       throw ("CPU STOPPED @ PC $" + hex(nes.cpu.REG_PC));
     };
     // insert debug hook
     nes.cpu._emulate = nes.cpu.emulate;
-    nes.cpu.emulate = function() {
+    nes.cpu.emulate = () => {
       var cycles = nes.cpu._emulate();
       //if (self.debugCondition && !self.debugBreakState && self.debugClock < 100) console.log(self.debugClock, nes.cpu.REG_PC);
-      self.evalDebugCondition();
+      this.evalDebugCondition();
       // TODO: doesn't stop on breakpoint
       return cycles;
     }
     timer = new AnimationTimer(60, this.nextFrame.bind(this));
     // set keyboard map
-    setKeyboardFromMap(video, [], JSNES_KEYCODE_MAP, function(o,key,code,flags) {
+    setKeyboardFromMap(video, [], JSNES_KEYCODE_MAP, (o,key,code,flags) => {
       if (flags & KeyFlags.KeyDown)
         nes.buttonDown(o.index+1, o.mask); // controller, button
       else if (flags & KeyFlags.KeyUp)
         nes.buttonUp(o.index+1, o.mask); // controller, button
     });
   }
-  
+
   advance(novideo : boolean) {
     try {
       nes.frame();
@@ -156,7 +156,7 @@ const _JSNESPlatform = function(mainElement) {
       this.breakpointHit(this.debugClock);
     }
   }
-  
+
   updateDebugViews() {
    // don't update if view is hidden
    if (! $(ntvideo.canvas).is(":visible"))
@@ -208,7 +208,7 @@ const _JSNESPlatform = function(mainElement) {
     return (this.readAddress(0xfffa) | (this.readAddress(0xfffb) << 8)) & 0xffff;
   }
   getDefaultExtension() { return ".c"; };
-  
+
   reset() {
     //nes.cpu.reset(); // doesn't work right, crashes
     nes.cpu.requestIrq(nes.cpu.IRQ_RESET);
diff --git a/src/project.ts b/src/project.ts
index c0422098..a74ac78c 100644
--- a/src/project.ts
+++ b/src/project.ts
@@ -7,7 +7,7 @@ type BuildResultCallback = (result:WorkerResult) => void;
 type BuildStatusCallback = (busy:boolean) => void;
 type LoadFilesCallback = (err:string, result?:Dependency[]) => void;
 type IterateFilesCallback = (path:string, data:FileData) => void;
-type GetRemoteCallback = any; // TODO (path:string, (text:string) => FileData) => void;
+type GetRemoteCallback = (path:string, callback:(data:FileData) => void, datatype:'text'|'arraybuffer') => any;
 
 export class CodeProject {
   filedata : {[path:string]:FileData} = {};
@@ -36,7 +36,7 @@ export class CodeProject {
       this.receiveWorkerMessage(e.data);
     };
   }
-  
+
   receiveWorkerMessage(data : WorkerResult) {
     var notfinal = this.pendingWorkerMessages > 1;
     if (notfinal) {
@@ -61,7 +61,7 @@ export class CodeProject {
       this.tools_preloaded[tool] = true;
     }
   }
-  
+
   pushAllFiles(files:string[], fn:string) {
     // look for local and preset files
     files.push('local/'+fn);
@@ -71,7 +71,7 @@ export class CodeProject {
     if (dir.length > 0 && dir != 'local') // TODO
       files.push(dir + '/' + fn);
   }
-  
+
   parseIncludeDependencies(text:string):string[] {
     var files = [];
     var m;
@@ -94,7 +94,7 @@ export class CodeProject {
     } else {
       // for .asm -- [.]include "file"
       // for .c -- #include "file"
-      var re2 = /^\s*([.#]?include|incbin)\s+"(.+?)"/gmi;
+      var re2 = /^\s*[.#]?(include|incbin)\s+"(.+?)"/gmi;
       while (m = re2.exec(text)) {
         this.pushAllFiles(files, m[2]);
       }
@@ -208,14 +208,16 @@ export class CodeProject {
               if (this.platform_id.startsWith('vcs') && path.indexOf('.') <= 0)
                 webpath += ".a"; // legacy stuff
               // try to GET file, use file ext to determine text/binary
-              this.callbackGetRemote( webpath, (text:FileData) => {
-                console.log("GET",webpath,text.length,'bytes');
-                this.filedata[path] = text; // do not update store, just cache
-                addResult(path, text);
+              this.callbackGetRemote( webpath, (data:FileData) => {
+                if (data instanceof ArrayBuffer)
+                  data = new Uint8Array(data); // convert to typed array
+                console.log("GET",webpath,data.length,'bytes');
+                this.filedata[path] = data; // do not update store, just cache
+                addResult(path, data);
                 loadNext();
               }, isProbablyBinary(path) ? 'arraybuffer' : 'text')
               .fail( (err:XMLHttpRequest) => {
-                console.log("Could not load preset", path, err.status);
+                console.log("Could not load preset file", path, err.status);
                 // only cache result if status is 404 (not found)
                 if (err.status && err.status == 404)
                   this.filedata[path] = null; // mark cache entry as invalid
diff --git a/src/ui.ts b/src/ui.ts
index 7d232c12..d73e851b 100644
--- a/src/ui.ts
+++ b/src/ui.ts
@@ -94,10 +94,21 @@ function setLastPreset(id:string) {
   }
 }
 
+// firefox doesn't do GET with binary files
+function getWithBinary(url:string, success:(text:FileData)=>void, datatype:'text'|'arraybuffer') {
+  var oReq = new XMLHttpRequest();
+  oReq.open("GET", url, true);
+  oReq.responseType = datatype;
+  oReq.onload = function (oEvent) {
+    success(oReq.response);
+  }
+  oReq.send(null);
+}
+
 function initProject() {
   current_project = new CodeProject(newWorker(), platform_id, platform, store);
   projectWindows = new ProjectWindows($("#workspace")[0] as HTMLElement, current_project);
-  current_project.callbackGetRemote = $.get;
+  current_project.callbackGetRemote = getWithBinary;
   current_project.callbackBuildResult = (result:WorkerResult) => {
     setCompileOutput(result);
     refreshWindowList();
diff --git a/src/worker/workermain.ts b/src/worker/workermain.ts
index dab3e89d..03f7b5c4 100644
--- a/src/worker/workermain.ts
+++ b/src/worker/workermain.ts
@@ -712,6 +712,8 @@ function assembleDASM(step:BuildStep) {
       }
     } else if (s.startsWith("Warning:")) {
       errors.push({line:0, msg:s.substr(9)});
+    } else if (s.startsWith("unable ")) {
+      errors.push({line:0, msg:s});
     } else {
       errorMatcher(s);
     }
diff --git a/tss b/tss
index 5b5ee67f..d630ddcb 160000
--- a/tss
+++ b/tss
@@ -1 +1 @@
-Subproject commit 5b5ee67fc06956bc7dce51726e98812d2d897eaa
+Subproject commit d630ddcb29d74a178cde043d74188fac35d6a21f