diff --git a/source/Disk.cpp b/source/Disk.cpp
index 1637d007..ae8411e9 100644
--- a/source/Disk.cpp
+++ b/source/Disk.cpp
@@ -1050,7 +1050,10 @@ void __stdcall Disk2InterfaceCard::ReadWrite(WORD pc, WORD addr, BYTE bWrite, BY
 		ReadTrack(m_currDrive, uExecutedCycles);
 
 	if (!pFloppy->m_trackimagedata)
+	{
+		pDrive->SetLastReadTrackSector(0);
 		return UpdateLatchForEmptyDrive(pDrive);
+	}
 
 	// Improve precision of "authentic" drive mode - GH#125
 	UINT uSpinNibbleCount = 0;
diff --git a/source/Disk.h b/source/Disk.h
index 67c44db6..ae1e6ae2 100644
--- a/source/Disk.h
+++ b/source/Disk.h
@@ -115,14 +115,25 @@ public:
 		m_headWindow = 0;
 		m_spinning = 0;
 		m_writelight = 0;
+		m_LastReadTrackSector[0] = -1;
+		m_LastReadTrackSector[1] = -1;
 		m_disk.clear();
 	}
 
 	// NOTE: Managed by Disk2InterfaceCard::ReadWrite()
 	void SetLastReadTrackSector(BYTE* pVolumeTrackSectorChecksum)
 	{
-		m_LastReadTrackSector[0] = pVolumeTrackSectorChecksum[1];
-		m_LastReadTrackSector[1] = pVolumeTrackSectorChecksum[2];
+		if (pVolumeTrackSectorChecksum)
+		{
+			m_LastReadTrackSector[0] = pVolumeTrackSectorChecksum[1];
+			m_LastReadTrackSector[1] = pVolumeTrackSectorChecksum[2];
+		}
+		else
+		{
+			m_LastReadTrackSector[0] = -1;
+			m_LastReadTrackSector[1] = -1;
+		}
+		assert(m_LastReadTrackSector[0] <= 80);
 	}
 
 public: