diff --git a/source/Disk.cpp b/source/Disk.cpp
index 357e9ee2..96a029a7 100644
--- a/source/Disk.cpp
+++ b/source/Disk.cpp
@@ -1206,7 +1206,7 @@ static void DiskSaveSnapshotDisk2Unit(YamlSaveHelper& yamlSaveHelper, UINT unit)
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_TRACK, g_aFloppyDisk[unit].track);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_PHASE, g_aFloppyDisk[unit].phase);
 	yamlSaveHelper.SaveHex16(SS_YAML_KEY_BYTE, g_aFloppyDisk[unit].byte);
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_WRITE_PROTECTED, g_aFloppyDisk[unit].bWriteProtected);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_WRITE_PROTECTED, g_aFloppyDisk[unit].bWriteProtected);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_SPINNING, g_aFloppyDisk[unit].spinning);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_WRITE_LIGHT, g_aFloppyDisk[unit].writelight);
 	yamlSaveHelper.SaveHex16(SS_YAML_KEY_NIBBLES, g_aFloppyDisk[unit].nibbles);
@@ -1227,11 +1227,11 @@ void DiskSaveSnapshot(class YamlSaveHelper& yamlSaveHelper)
 	YamlSaveHelper::Label state(yamlSaveHelper, "%s:\n", SS_YAML_KEY_STATE);
 	yamlSaveHelper.SaveHex4(SS_YAML_KEY_PHASES, phases);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_CURRENT_DRIVE, currdrive);
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_DISK_ACCESSED, diskaccessed);
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_ENHANCE_DISK, enhancedisk);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_DISK_ACCESSED, diskaccessed == TRUE);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_ENHANCE_DISK, enhancedisk == TRUE);
 	yamlSaveHelper.SaveHex8(SS_YAML_KEY_FLOPPY_LATCH, floppylatch);
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_FLOPPY_MOTOR_ON, floppymotoron);
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_FLOPPY_WRITE_MODE, floppywritemode);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_FLOPPY_MOTOR_ON, floppymotoron == TRUE);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_FLOPPY_WRITE_MODE, floppywritemode == TRUE);
 
 	DiskSaveSnapshotDisk2Unit(yamlSaveHelper, DRIVE_1);
 	DiskSaveSnapshotDisk2Unit(yamlSaveHelper, DRIVE_2);
@@ -1277,7 +1277,7 @@ static void DiskLoadSnapshotDriveUnit(YamlLoadHelper& yamlLoadHelper, UINT unit)
 	g_aFloppyDisk[unit].track			= yamlLoadHelper.LoadUint(SS_YAML_KEY_TRACK);
 	g_aFloppyDisk[unit].phase			= yamlLoadHelper.LoadUint(SS_YAML_KEY_PHASE);
 	g_aFloppyDisk[unit].byte			= yamlLoadHelper.LoadUint(SS_YAML_KEY_BYTE);
-	yamlLoadHelper.LoadUint(SS_YAML_KEY_WRITE_PROTECTED);	// Consume
+	yamlLoadHelper.LoadBool(SS_YAML_KEY_WRITE_PROTECTED);	// Consume
 	g_aFloppyDisk[unit].spinning		= yamlLoadHelper.LoadUint(SS_YAML_KEY_SPINNING);
 	g_aFloppyDisk[unit].writelight		= yamlLoadHelper.LoadUint(SS_YAML_KEY_WRITE_LIGHT);
 	g_aFloppyDisk[unit].nibbles			= yamlLoadHelper.LoadUint(SS_YAML_KEY_NIBBLES);
@@ -1325,11 +1325,11 @@ bool DiskLoadSnapshot(class YamlLoadHelper& yamlLoadHelper, UINT slot, UINT vers
 
 	phases  		= yamlLoadHelper.LoadUint(SS_YAML_KEY_PHASES);
 	currdrive		= yamlLoadHelper.LoadUint(SS_YAML_KEY_CURRENT_DRIVE);
-	diskaccessed	= yamlLoadHelper.LoadUint(SS_YAML_KEY_DISK_ACCESSED);
-	enhancedisk		= yamlLoadHelper.LoadUint(SS_YAML_KEY_ENHANCE_DISK);
+	diskaccessed	= yamlLoadHelper.LoadBool(SS_YAML_KEY_DISK_ACCESSED);
+	enhancedisk		= yamlLoadHelper.LoadBool(SS_YAML_KEY_ENHANCE_DISK);
 	floppylatch		= yamlLoadHelper.LoadUint(SS_YAML_KEY_FLOPPY_LATCH);
-	floppymotoron	= yamlLoadHelper.LoadUint(SS_YAML_KEY_FLOPPY_MOTOR_ON);
-	floppywritemode	= yamlLoadHelper.LoadUint(SS_YAML_KEY_FLOPPY_WRITE_MODE);
+	floppymotoron	= yamlLoadHelper.LoadBool(SS_YAML_KEY_FLOPPY_MOTOR_ON);
+	floppywritemode	= yamlLoadHelper.LoadBool(SS_YAML_KEY_FLOPPY_WRITE_MODE);
 
 	// Eject all disks first in case Drive-2 contains disk to be inserted into Drive-1
 	for(UINT i=0; i<NUM_DRIVES; i++)
diff --git a/source/Harddisk.cpp b/source/Harddisk.cpp
index 6e4eeaf3..83c0b953 100644
--- a/source/Harddisk.cpp
+++ b/source/Harddisk.cpp
@@ -692,7 +692,7 @@ static void HD_SaveSnapshotHDDUnit(YamlSaveHelper& yamlSaveHelper, UINT unit)
 	yamlSaveHelper.SaveHex8(SS_YAML_KEY_ERROR, g_HardDisk[unit].hd_error);
 	yamlSaveHelper.SaveHex16(SS_YAML_KEY_MEMBLOCK, g_HardDisk[unit].hd_memblock);
 	yamlSaveHelper.SaveHex32(SS_YAML_KEY_DISKBLOCK, g_HardDisk[unit].hd_diskblock);
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_IMAGELOADED, g_HardDisk[unit].hd_imageloaded);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_IMAGELOADED, g_HardDisk[unit].hd_imageloaded);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_STATUS_NEXT, g_HardDisk[unit].hd_status_next);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_STATUS_PREV, g_HardDisk[unit].hd_status_prev);
 	yamlSaveHelper.SaveHex16(SS_YAML_KEY_BUF_PTR, g_HardDisk[unit].hd_buf_ptr);
diff --git a/source/Mockingboard.cpp b/source/Mockingboard.cpp
index b70dd84c..0451dc65 100644
--- a/source/Mockingboard.cpp
+++ b/source/Mockingboard.cpp
@@ -1987,9 +1987,9 @@ void MB_SaveSnapshot(YamlSaveHelper& yamlSaveHelper, const UINT uSlot)
 		SaveSnapshotSSI263(yamlSaveHelper, pMB->SpeechChip);
 
 		yamlSaveHelper.SaveHex4(SS_YAML_KEY_AY_CURR_REG, pMB->nAYCurrentRegister);
-		yamlSaveHelper.Save("%s: %d # Not supported\n", SS_YAML_KEY_TIMER1_IRQ, 0);
-		yamlSaveHelper.Save("%s: %d # Not supported\n", SS_YAML_KEY_TIMER2_IRQ, 0);
-		yamlSaveHelper.Save("%s: %d # Not supported\n", SS_YAML_KEY_SPEECH_IRQ, 0);
+		yamlSaveHelper.Save("%s: %s # Not supported\n", SS_YAML_KEY_TIMER1_IRQ, "false");
+		yamlSaveHelper.Save("%s: %s # Not supported\n", SS_YAML_KEY_TIMER2_IRQ, "false");
+		yamlSaveHelper.Save("%s: %s # Not supported\n", SS_YAML_KEY_SPEECH_IRQ, "false");
 
 		nDeviceNum++;
 		pMB++;
@@ -2063,9 +2063,9 @@ bool MB_LoadSnapshot(YamlLoadHelper& yamlLoadHelper, UINT slot, UINT version)
 		LoadSnapshotSSI263(yamlLoadHelper, pMB->SpeechChip);
 
 		pMB->nAYCurrentRegister = yamlLoadHelper.LoadUint(SS_YAML_KEY_AY_CURR_REG);
-		yamlLoadHelper.LoadUint(SS_YAML_KEY_TIMER1_IRQ);	// Consume
-		yamlLoadHelper.LoadUint(SS_YAML_KEY_TIMER2_IRQ);	// Consume
-		yamlLoadHelper.LoadUint(SS_YAML_KEY_SPEECH_IRQ);	// Consume
+		yamlLoadHelper.LoadBool(SS_YAML_KEY_TIMER1_IRQ);	// Consume
+		yamlLoadHelper.LoadBool(SS_YAML_KEY_TIMER2_IRQ);	// Consume
+		yamlLoadHelper.LoadBool(SS_YAML_KEY_SPEECH_IRQ);	// Consume
 
 		yamlLoadHelper.PopMap();
 
@@ -2127,9 +2127,9 @@ void Phasor_SaveSnapshot(YamlSaveHelper& yamlSaveHelper, const UINT uSlot)
 		SaveSnapshotSSI263(yamlSaveHelper, pMB->SpeechChip);
 
 		yamlSaveHelper.SaveHex4(SS_YAML_KEY_AY_CURR_REG, pMB->nAYCurrentRegister);
-		yamlSaveHelper.Save("%s: %d # Not supported\n", SS_YAML_KEY_TIMER1_IRQ, 0);
-		yamlSaveHelper.Save("%s: %d # Not supported\n", SS_YAML_KEY_TIMER2_IRQ, 0);
-		yamlSaveHelper.Save("%s: %d # Not supported\n", SS_YAML_KEY_SPEECH_IRQ, 0);
+		yamlSaveHelper.Save("%s: %s # Not supported\n", SS_YAML_KEY_TIMER1_IRQ, "false");
+		yamlSaveHelper.Save("%s: %s # Not supported\n", SS_YAML_KEY_TIMER2_IRQ, "false");
+		yamlSaveHelper.Save("%s: %s # Not supported\n", SS_YAML_KEY_SPEECH_IRQ, "false");
 
 		nDeviceNum += 2;
 		pMB++;
@@ -2168,9 +2168,9 @@ bool Phasor_LoadSnapshot(YamlLoadHelper& yamlLoadHelper, UINT slot, UINT version
 		LoadSnapshotSSI263(yamlLoadHelper, pMB->SpeechChip);
 
 		pMB->nAYCurrentRegister = yamlLoadHelper.LoadUint(SS_YAML_KEY_AY_CURR_REG);
-		yamlLoadHelper.LoadUint(SS_YAML_KEY_TIMER1_IRQ);	// Consume
-		yamlLoadHelper.LoadUint(SS_YAML_KEY_TIMER2_IRQ);	// Consume
-		yamlLoadHelper.LoadUint(SS_YAML_KEY_SPEECH_IRQ);	// Consume
+		yamlLoadHelper.LoadBool(SS_YAML_KEY_TIMER1_IRQ);	// Consume
+		yamlLoadHelper.LoadBool(SS_YAML_KEY_TIMER2_IRQ);	// Consume
+		yamlLoadHelper.LoadBool(SS_YAML_KEY_SPEECH_IRQ);	// Consume
 
 		yamlLoadHelper.PopMap();
 
diff --git a/source/ParallelPrinter.cpp b/source/ParallelPrinter.cpp
index f295c958..f17609db 100644
--- a/source/ParallelPrinter.cpp
+++ b/source/ParallelPrinter.cpp
@@ -282,7 +282,7 @@ void Printer_SaveSnapshot(class YamlSaveHelper& yamlSaveHelper)
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_INACTIVITY, inactivity);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_IDLELIMIT, g_PrinterIdleLimit);
 	yamlSaveHelper.SaveString(SS_YAML_KEY_FILENAME, g_szPrintFilename);
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_FILEOPEN, (file != NULL) ? 1 : 0);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_FILEOPEN, (file != NULL) ? true : false);
 	yamlSaveHelper.SaveBool(SS_YAML_KEY_DUMPTOPRINTER, g_bDumpToPrinter);
 	yamlSaveHelper.SaveBool(SS_YAML_KEY_CONVERTENCODING, g_bConvertEncoding);
 	yamlSaveHelper.SaveBool(SS_YAML_KEY_FILTERUNPRINTABLE, g_bFilterUnprintable);
diff --git a/source/Video.cpp b/source/Video.cpp
index e391ae0c..02d3720e 100644
--- a/source/Video.cpp
+++ b/source/Video.cpp
@@ -2963,7 +2963,7 @@ static std::string VideoGetSnapshotStructName(void)
 void VideoSaveSnapshot(YamlSaveHelper& yamlSaveHelper)
 {
 	YamlSaveHelper::Label state(yamlSaveHelper, "%s:\n", VideoGetSnapshotStructName().c_str());
-	yamlSaveHelper.SaveUint(SS_YAML_KEY_ALTCHARSET, g_nAltCharSetOffset ? 1 : 0);
+	yamlSaveHelper.SaveBool(SS_YAML_KEY_ALTCHARSET, g_nAltCharSetOffset ? true : false);
 	yamlSaveHelper.SaveHex32(SS_YAML_KEY_VIDEOMODE, g_uVideoMode);
 	yamlSaveHelper.SaveUint(SS_YAML_KEY_CYCLESTHISFRAME, g_dwCyclesThisFrame);
 }
@@ -2973,7 +2973,7 @@ void VideoLoadSnapshot(YamlLoadHelper& yamlLoadHelper)
 	if (!yamlLoadHelper.GetSubMap(VideoGetSnapshotStructName()))
 		return;
 
-	g_nAltCharSetOffset = yamlLoadHelper.LoadUint(SS_YAML_KEY_ALTCHARSET) ? 256 : 0;
+	g_nAltCharSetOffset = yamlLoadHelper.LoadBool(SS_YAML_KEY_ALTCHARSET) ? 256 : 0;
 	g_uVideoMode = yamlLoadHelper.LoadUint(SS_YAML_KEY_VIDEOMODE);
 	g_dwCyclesThisFrame = yamlLoadHelper.LoadUint(SS_YAML_KEY_CYCLESTHISFRAME);
 
diff --git a/source/YamlHelper.cpp b/source/YamlHelper.cpp
index 4a415f3b..bc304b6d 100644
--- a/source/YamlHelper.cpp
+++ b/source/YamlHelper.cpp
@@ -313,7 +313,14 @@ UINT64 YamlLoadHelper::LoadUint64(const std::string key)
 
 bool YamlLoadHelper::LoadBool(const std::string key)
 {
-	return LoadUint(key) ? true : false;
+	bool bFound;
+	std::string value = m_yamlHelper.GetMapValue(*m_pMapYaml, key, bFound);
+	if (value == "true")
+		return true;
+	else if (value == "false")
+		return false;
+	m_bDoGetMapRemainder = false;
+	throw std::string(m_currentMapName + ": Missing: " + key);
 }
 
 std::string YamlLoadHelper::LoadString_NoThrow(const std::string& key, bool& bFound)
@@ -393,7 +400,7 @@ void YamlSaveHelper::SaveHex64(const char* key, UINT64 value)
 
 void YamlSaveHelper::SaveBool(const char* key, bool value)
 {
-	SaveUint(key, value ? 1 : 0);
+	Save("%s: %s\n", key, value ? "true" : "false");
 }
 
 void YamlSaveHelper::SaveString(const char* key,  const char* value)
@@ -401,8 +408,12 @@ void YamlSaveHelper::SaveString(const char* key,  const char* value)
 	Save("%s: %s\n", key, (value[0] != 0) ? value : "\"\"");
 }
 
+// Pre: uMemSize must be multiple of 8
 void YamlSaveHelper::SaveMemory(const LPBYTE pMemBase, const UINT uMemSize)
 {
+	if (uMemSize & 7)
+		throw std::string("Memory: size must be multiple of 8");
+
 	const UINT kIndent = m_indent;
 
 	const UINT kStride = 64;