diff --git a/source/Disk.cpp b/source/Disk.cpp
index f9c095a9..c90c5447 100644
--- a/source/Disk.cpp
+++ b/source/Disk.cpp
@@ -1073,7 +1073,7 @@ void __stdcall Disk2InterfaceCard::DataLatchReadWriteWOZ(WORD pc, WORD addr, BYT
 	// The first 1-bit will produce a latch nibble, and this 1-bit is unlikely to be the nibble's high bit.
 	// So we need to ensure we run enough bits through the sequencer to re-sync.
 	// NB. For Planetfall 13 bitcells(NG) / 14 bitcells(OK)
-	const UINT significantBitCells = 50;	// 5x 10-bit sync FF nibbles
+	const UINT significantBitCells = floppy.m_bitCount;
 	UINT bitCellDelta = GetBitCellDelta(ImageGetOptimalBitTiming(floppy.m_imagehandle));
 
 	UINT bitCellRemainder;
@@ -1113,6 +1113,8 @@ void __stdcall Disk2InterfaceCard::DataLatchReadWriteWOZ(WORD pc, WORD addr, BYT
 		FrameDrawDiskStatus((HDC)0);
 }
 
+static int g_zeroFieldFlag = 1;
+static int g_zeroFieldCount = 0;
 void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemainder)
 {
 	// m_diskLastReadLatchCycle = g_nCumulativeCycles;	// Not used by WOZ (only by NIB)
@@ -1136,7 +1138,7 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
 #endif
 
 	// Only extraCycles of 2 & 3 can hold the latch for another bitCell period, eg. m_latchDelay: 3->5 or 7->9
-	UINT extraLatchDelay = ((UINT)floppy.m_extraCycles >= 2) ? 2 : 0;	// GH#733 (0,1->0; 2,3->2)
+//	UINT extraLatchDelay = ((UINT)floppy.m_extraCycles >= 2) ? 2 : 0;	// GH#733 (0,1->0; 2,3->2)
 
 	for (UINT i = 0; i < bitCellRemainder; i++)
 	{
@@ -1147,6 +1149,23 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
 		BYTE outputBit = (drive.m_headWindow & 0xf)	? (drive.m_headWindow >> 1) & 1
 													: (rand() < ((RAND_MAX * 3) / 10)) ? 1 : 0;	// ~30% chance of a 1 bit (Ref: WOZ-2.0)
 
+#if 0	// DEBUG: insert an extra 0-bit into the field of 317 zero bits
+		bool doInc = true;
+		if (drive.m_phase == 0 && floppy.m_bitOffset == (0x5811 + 92))
+		{
+			g_zeroFieldCount++;
+			if (regs.pc < 0x8ff)
+			{
+				if (g_zeroFieldFlag)
+				{
+					g_zeroFieldFlag = 0;
+					doInc = false;
+				}
+			}
+		}
+		if (doInc)
+#endif
+		{
 		floppy.m_bitMask >>= 1;
 		if (!floppy.m_bitMask)
 		{
@@ -1161,6 +1180,7 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
 			floppy.m_bitOffset = 0;
 			floppy.m_byte = 0;
 		}
+		}
 
 		if (m_resetSequencer)
 		{
@@ -1175,9 +1195,9 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
 
 		if (m_latchDelay)
 		{
-			if (i == bitCellRemainder-1)			// On last bitCell
-				m_latchDelay += extraLatchDelay;	// +0 or +2
-			extraLatchDelay = 0;					// and always clear (even when not last bitCell)
+//			if (i == bitCellRemainder-1)			// On last bitCell
+//				m_latchDelay += extraLatchDelay;	// +0 or +2
+//			extraLatchDelay = 0;					// and always clear (even when not last bitCell)
 
 			m_latchDelay -= 4;
 			if (m_latchDelay < 0)
diff --git a/source/DiskImageHelper.cpp b/source/DiskImageHelper.cpp
index de14a95a..5a3aff20 100644
--- a/source/DiskImageHelper.cpp
+++ b/source/DiskImageHelper.cpp
@@ -1190,6 +1190,23 @@ public:
 			return ReadEmptyTrack(pTrackImageBuffer, pNibbles, pBitCount);	// TODO: Enlarge track buffer, but for now just return an empty track
 
 		memcpy(pTrackImageBuffer, &pImageInfo->pImageBuffer[pTRK->startBlock*CWOZHelper::BLOCK_SIZE], *pNibbles);
+#if 0	// DEBUG: insert an extra 0-bit into the field of 317 zero bits
+		if (phase == 0)
+		{
+			UINT offset = 0x5870/8;	//0x5811 + 92 = 0x586D
+			BYTE c = 0;
+			while (offset < (UINT)*pNibbles)
+			{
+				BYTE d = pTrackImageBuffer[offset];
+				BYTE n = (c<<7) | (d>>1);
+				c = d&1;
+				pTrackImageBuffer[offset] = n;
+				offset++;
+			}
+			(*pBitCount)++;
+			*pNibbles = (pTRK->bitCount+7) / 8;
+		}
+#endif
 	}
 
 	virtual void Write(ImageInfo* pImageInfo, const float phase, LPBYTE pTrackImageBuffer, int nNibbles)