diff --git a/include/dos_inc.h b/include/dos_inc.h
index 40ecb195..753af672 100644
--- a/include/dos_inc.h
+++ b/include/dos_inc.h
@@ -386,6 +386,7 @@ public:
 	void SetDiskBufferHeadPt(Bit32u _dbheadpt);
 	void SetStartOfUMBChain(Bit16u _umbstartseg);
 	void SetUMBChainState(Bit8u _umbchaining);
+	void SetBlockDevices(Bit8u _count);
 	Bit16u	GetStartOfUMBChain(void);
 	Bit8u	GetUMBChainState(void);
 	RealPt	GetPointer(void);
diff --git a/src/dos/dos.cpp b/src/dos/dos.cpp
index 897b6880..d5cb2b8b 100644
--- a/src/dos/dos.cpp
+++ b/src/dos/dos.cpp
@@ -840,6 +840,9 @@ static Bitu DOS_21Handler(void) {
 		reg_bx=dos.psp();
 		break;
 	case 0x52: {				/* Get list of lists */
+		Bit8u count=2; // floppy drives always counted
+		while (count<DOS_DRIVES && Drives[count] && !Drives[count]->isRemovable()) count++;
+		dos_infoblock.SetBlockDevices(count);
 		RealPt addr=dos_infoblock.GetPointer();
 		SegSet16(es,RealSeg(addr));
 		reg_bx=RealOff(addr);
@@ -1171,22 +1174,28 @@ static Bitu DOS_27Handler(void) {
 }
 
 static Bitu DOS_25Handler(void) {
-	if (Drives[reg_al] == 0){
+	if (reg_al >= DOS_DRIVES || !Drives[reg_al] || Drives[reg_al]->isRemovable()) {
 		reg_ax = 0x8002;
 		SETFLAGBIT(CF,true);
 	} else {
+		if (reg_cx == 1 && reg_dx == 0) {
+			if (reg_al >= 2) {
+				PhysPt ptr = PhysMake(SegValue(ds),reg_bx);
+				// write some BPB data into buffer for MicroProse installers
+				mem_writew(ptr+0x1c,0x3f); // hidden sectors
+			}
+		} else {
+			LOG(LOG_DOSMISC,LOG_NORMAL)("int 25 called but not as disk detection drive %u",reg_al);
+		}
 		SETFLAGBIT(CF,false);
-		if ((reg_cx != 1) ||(reg_dx != 1))
-			LOG(LOG_DOSMISC,LOG_NORMAL)("int 25 called but not as diskdetection drive %X",reg_al);
-
-	   reg_ax = 0;
+		reg_ax = 0;
 	}
 	SETFLAGBIT(IF,true);
     return CBRET_NONE;
 }
 static Bitu DOS_26Handler(void) {
 	LOG(LOG_DOSMISC,LOG_NORMAL)("int 26 called: hope for the best!");
-	if (Drives[reg_al] == 0){
+	if (reg_al >= DOS_DRIVES || !Drives[reg_al] || Drives[reg_al]->isRemovable()) {	
 		reg_ax = 0x8002;
 		SETFLAGBIT(CF,true);
 	} else {
diff --git a/src/dos/dos_classes.cpp b/src/dos/dos_classes.cpp
index 3df73f2e..d407b04d 100644
--- a/src/dos/dos_classes.cpp
+++ b/src/dos/dos_classes.cpp
@@ -157,6 +157,10 @@ void DOS_InfoBlock::SetUMBChainState(Bit8u _umbchaining) {
 	sSave(sDIB,chainingUMB,_umbchaining);
 }
 
+void DOS_InfoBlock::SetBlockDevices(Bit8u _count) {
+	sSave(sDIB,blockDevices,_count);
+}
+
 RealPt DOS_InfoBlock::GetPointer(void) {
 	return RealMake(seg,offsetof(sDIB,firstDPB));
 }
diff --git a/src/ints/bios_disk.cpp b/src/ints/bios_disk.cpp
index 863b88ad..c3683db4 100644
--- a/src/ints/bios_disk.cpp
+++ b/src/ints/bios_disk.cpp
@@ -366,8 +366,19 @@ static Bitu INT13_DiskHandler(void) {
 			return CBRET_NONE;
 		}
 		if (!any_images) {
-			// Inherit the Earth cdrom (uses it as disk test)
+			if (drivenum >= DOS_DRIVES || !Drives[drivenum] || Drives[drivenum]->isRemovable()) {
+				reg_ah = 0x01;
+				CALLBACK_SCF(true);
+				return CBRET_NONE;
+			}
+			// Inherit the Earth cdrom and Amberstar use it as a disk test
 			if (((reg_dl&0x80)==0x80) && (reg_dh==0) && ((reg_cl&0x3f)==1)) {
+				if (reg_ch==0) {
+					PhysPt ptr = PhysMake(SegValue(es),reg_bx);
+					// write some MBR data into buffer for Amberstar installer
+					mem_writeb(ptr+0x1be,0x80); // first partition is active
+					mem_writeb(ptr+0x1c2,0x06); // first partition is FAT16B
+				}
 				reg_ah = 0;
 				CALLBACK_SCF(false);
 				return CBRET_NONE;