diff --git a/src/dos/dos_mscdex.cpp b/src/dos/dos_mscdex.cpp
index d33af13d..c1c96c24 100644
--- a/src/dos/dos_mscdex.cpp
+++ b/src/dos/dos_mscdex.cpp
@@ -933,7 +933,7 @@ static CMscdex* mscdex = 0;
 static PhysPt curReqheaderPtr = 0;
 
 static Bit16u MSCDEX_IOCTL_Input(PhysPt buffer,Bit8u drive_unit) {
-	Bitu ioctl_fct = mem_readb(buffer);
+	Bit8u ioctl_fct = mem_readb(buffer);
 	MSCDEX_LOG("MSCDEX: IOCTL INPUT Subfunction %02X",ioctl_fct);
 	switch (ioctl_fct) {
 		case 0x00 : /* Get Device Header address */
@@ -1050,7 +1050,7 @@ static Bit16u MSCDEX_IOCTL_Input(PhysPt buffer,Bit8u drive_unit) {
 }
 
 static Bit16u MSCDEX_IOCTL_Optput(PhysPt buffer,Bit8u drive_unit) {
-	Bitu ioctl_fct = mem_readb(buffer);
+	Bit8u ioctl_fct = mem_readb(buffer);
 //	MSCDEX_LOG("MSCDEX: IOCTL OUTPUT Subfunction %02X",ioctl_fct);
 	switch (ioctl_fct) {
 		case 0x00 :	// Unload /eject media