diff --git a/src/main/fragment/cache/fragment-cache-mos6502.asm b/src/main/fragment/cache/fragment-cache-mos6502.asm
index c8f402d23..06affc4ac 100644
--- a/src/main/fragment/cache/fragment-cache-mos6502.asm
+++ b/src/main/fragment/cache/fragment-cache-mos6502.asm
@@ -1,4 +1,4 @@
-//KICKC FRAGMENT CACHE 160b017651
+//KICKC FRAGMENT CACHE 160b015f22
 //FRAGMENT vbuz1=vbuc1
 lda #{c1}
 sta {z1}
diff --git a/src/main/fragment/cache/fragment-cache-mos6502x.asm b/src/main/fragment/cache/fragment-cache-mos6502x.asm
index 8e2321752..529c3fcfe 100644
--- a/src/main/fragment/cache/fragment-cache-mos6502x.asm
+++ b/src/main/fragment/cache/fragment-cache-mos6502x.asm
@@ -1,4 +1,4 @@
-//KICKC FRAGMENT CACHE 160b017651
+//KICKC FRAGMENT CACHE 160b015f22
 //FRAGMENT vbuz1=vbuc1
 lda #{c1}
 sta {z1}
@@ -8562,6 +8562,52 @@ sty {z1}
 //FRAGMENT _deref_pbsc1=vbsc2
 lda #{c2}
 sta {c1}
+//FRAGMENT vbuz1=_dec_vbuz2
+ldy {z2}
+dey
+sty {z1}
+//FRAGMENT vbuz1=_dec_vbuaa
+sec
+sbc #1
+sta {z1}
+//FRAGMENT vbuz1=_dec_vbuxx
+dex
+stx {z1}
+//FRAGMENT vbuz1=_dec_vbuyy
+dey
+sty {z1}
+//FRAGMENT vbuaa=_dec_vbuz1
+lda {z1}
+sec
+sbc #1
+//FRAGMENT vbuaa=_dec_vbuxx
+txa
+sec
+sbc #1
+//FRAGMENT vbuaa=_dec_vbuyy
+tya
+sec
+sbc #1
+//FRAGMENT vbuxx=_dec_vbuz1
+ldx {z1}
+dex
+//FRAGMENT vbuxx=_dec_vbuaa
+tax
+dex
+//FRAGMENT vbuxx=_dec_vbuyy
+tya
+tax
+dex
+//FRAGMENT vbuyy=_dec_vbuz1
+ldy {z1}
+dey
+//FRAGMENT vbuyy=_dec_vbuaa
+tay
+dey
+//FRAGMENT vbuyy=_dec_vbuxx
+txa
+tay
+dey
 //FRAGMENT vwuz1=vwuz2_bor_vbuz3
 lda {z3}
 ora {z2}
@@ -17737,49 +17783,3 @@ sta {c1},x
 lda #{c2}
 ora {c1},y
 sta {c1},y
-//FRAGMENT vbuz1=_dec_vbuz2
-ldy {z2}
-dey
-sty {z1}
-//FRAGMENT vbuz1=_dec_vbuaa
-sec
-sbc #1
-sta {z1}
-//FRAGMENT vbuz1=_dec_vbuxx
-dex
-stx {z1}
-//FRAGMENT vbuz1=_dec_vbuyy
-dey
-sty {z1}
-//FRAGMENT vbuaa=_dec_vbuz1
-lda {z1}
-sec
-sbc #1
-//FRAGMENT vbuaa=_dec_vbuxx
-txa
-sec
-sbc #1
-//FRAGMENT vbuaa=_dec_vbuyy
-tya
-sec
-sbc #1
-//FRAGMENT vbuxx=_dec_vbuz1
-ldx {z1}
-dex
-//FRAGMENT vbuxx=_dec_vbuaa
-tax
-dex
-//FRAGMENT vbuxx=_dec_vbuyy
-tya
-tax
-dex
-//FRAGMENT vbuyy=_dec_vbuz1
-ldy {z1}
-dey
-//FRAGMENT vbuyy=_dec_vbuaa
-tay
-dey
-//FRAGMENT vbuyy=_dec_vbuxx
-txa
-tay
-dey
diff --git a/src/test/kc/complex/lazynes/lazynes.c b/src/test/kc/complex/lazynes/lazynes.c
index 9ae0b3cf0..bbb0cf0f9 100644
--- a/src/test/kc/complex/lazynes/lazynes.c
+++ b/src/test/kc/complex/lazynes/lazynes.c
@@ -58,6 +58,17 @@ struct SpriteData align(0x100) SPRITE_BUFFER[0x40];
 // Index of the next SpriteData in SPRITE_BUFFER to write to in lnAddSpr()
 volatile char add_sprite_idx;
 
+// Counts the vblanks between syncs
+volatile char vblank_count;
+
+// The current mode set by lnSync. 
+//	lfBlank = 1,  activates blank mode, blanks screen and allows lnPush() calls
+//	lfSplit = 2   activates split mode, NMI waits for SPR0HIT and sets registers
+volatile char sync_mode;
+
+// Signal when vblank occurs. The NMI sets this to zero. To wait for a vblank set this no non-zero and wait for it to become zero.
+volatile char vblank_signal;
+
 // NMI Called when the PPU refreshes the screen (also known as the V-Blank period)
 interrupt(hardware_stack) void vblank() {
     // DMA transfer the entire sprite buffer to the PPU
@@ -65,36 +76,58 @@ interrupt(hardware_stack) void vblank() {
     // Set scroll
     PPU->PPUSCROLL = 0;
     PPU->PPUSCROLL = 0;
-    // move all sprites off the screen
-    //for(char i=0;i!=0x40;i++)
-    //    SPRITE_BUFFER[i].y = 0xff;
-    // Reset the index of sprites to add
-    add_sprite_idx = 0;
+    // count vblanks
+    vblank_count++;
+    // send vblank signal
+    vblank_signal = 0;
 }
 
    // Wait for next vblank
   // flags: 0, lfBlank or lfSplit (see below)
  // result: Amount of frames since last sync [0..31], 128 is added on NTSC
-//
+//	lfBlank = 0,  disables blank mode (if set), wait for vblank
+//	lfBlank = 1,  activates blank mode, blanks screen and allows lnPush() calls
+//	lfSplit = 2   activates split mode, NMI waits for SPR0HIT and sets registers
 ubyte lnSync(ubyte flags) {
-    // Enable video output if lfBlank not set
+    // Is video output enabled (lfBlank==0)
     if(!(flags&lfBlank)) {
-        // Set sprite tileset to upper - enable vblank NMI
-        PPU->PPUCTRL = 0b10001000;
-        // Enable sprite and tile rendering
-        PPU->PPUMASK = 0b00011110;    
+        // Move remaining sprites off the screen
+        for(char i=add_sprite_idx;i!=0x40;i++)
+            SPRITE_BUFFER[i].y = 0xff;
+        // Reset add sprite index
+        add_sprite_idx = 0;
+        // Enable video output (if it was disabled)
+        if(sync_mode&lfBlank) {
+            // Set sprite tileset to upper - enable vblank NMI
+            PPU->PPUCTRL = 0b10001000;
+            // Enable sprite and tile rendering
+            PPU->PPUMASK = 0b00011110;    
+        }
     }
     
-    // Wait for V-Blank
-    waitForVBlank();
+    // Wait for V-Blank signal from the NMI (if vblank is currently enabled)
+    if(!(sync_mode&lfBlank)) {
+        vblank_signal = 0xff;
+        while(vblank_signal) ;
+    }
+
     // Disable video output if lfBlank set
-    if(flags&lfBlank)
+    if(flags&lfBlank) {
         // lfBlank = 1, activates blank mode, blanks screen and allows lnPush() calls
-        disableVideoOutput();
+        // Disable vertical blank interrupt
+        PPU->PPUCTRL = 0;
+        // Disable sprite rendering
+        PPU->PPUMASK = 0;
+    }
+
+    // Update the mode
+    sync_mode = flags;
 
     // TODO: Handle lfSplit = 2 : activates split mode, NMI waits for SPR0HIT and sets registers
-   // TODO: Count frames
-    return 0;
+    // Return number of vblank since last sync
+    char res = vblank_count;
+    vblank_count = 0;
+    return res;
 }
 
      // Write data into nametables, palettes, CHRRAM, etc.