diff --git a/include/callback.h b/include/callback.h
index 53bc39c0..d1240ee2 100644
--- a/include/callback.h
+++ b/include/callback.h
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: callback.h,v 1.25 2009-06-11 16:05:17 c2woody Exp $ */
+/* $Id: callback.h,v 1.26 2009-08-23 17:24:54 c2woody Exp $ */
 
 #ifndef DOSBOX_CALLBACK_H
 #define DOSBOX_CALLBACK_H
@@ -71,6 +71,7 @@ bool CALLBACK_Free(Bitu callback);
 
 void CALLBACK_SCF(bool val);
 void CALLBACK_SZF(bool val);
+void CALLBACK_SIF(bool val);
 
 extern Bitu call_priv_io;
 
diff --git a/src/cpu/callback.cpp b/src/cpu/callback.cpp
index b5d88089..1d21062e 100644
--- a/src/cpu/callback.cpp
+++ b/src/cpu/callback.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: callback.cpp,v 1.41 2009-06-11 16:05:17 c2woody Exp $ */
+/* $Id: callback.cpp,v 1.42 2009-08-23 17:24:54 c2woody Exp $ */
 
 #include <stdlib.h>
 #include <string.h>
@@ -109,15 +109,24 @@ void CALLBACK_RunRealInt(Bit8u intnum) {
 }
 
 void CALLBACK_SZF(bool val) {
-	Bit16u tempf=mem_readw(SegPhys(ss)+reg_sp+4) & 0xFFBF;
-	Bit16u newZF=(val==true) << 6;
-	mem_writew(SegPhys(ss)+reg_sp+4,(tempf | newZF));
+	Bit16u tempf = mem_readw(SegPhys(ss)+reg_sp+4); 
+	if (val) tempf |= FLAG_ZF; 
+	else tempf &= ~FLAG_ZF; 
+	mem_writew(SegPhys(ss)+reg_sp+4,tempf); 
 }
 
 void CALLBACK_SCF(bool val) {
-	Bit16u tempf=mem_readw(SegPhys(ss)+reg_sp+4) & 0xFFFE;
-	Bit16u newCF=(val==true);
-	mem_writew(SegPhys(ss)+reg_sp+4,(tempf | newCF));
+	Bit16u tempf = mem_readw(SegPhys(ss)+reg_sp+4); 
+	if (val) tempf |= FLAG_CF; 
+	else tempf &= ~FLAG_CF; 
+	mem_writew(SegPhys(ss)+reg_sp+4,tempf); 
+}
+
+void CALLBACK_SIF(bool val) {
+	Bit16u tempf = mem_readw(SegPhys(ss)+reg_sp+4); 
+	if (val) tempf |= FLAG_IF; 
+	else tempf &= ~FLAG_IF; 
+	mem_writew(SegPhys(ss)+reg_sp+4,tempf); 
 }
 
 void CALLBACK_SetDescription(Bitu nr, const char* descr) {
diff --git a/src/ints/bios_disk.cpp b/src/ints/bios_disk.cpp
index 6fdafa6d..9b0289e4 100644
--- a/src/ints/bios_disk.cpp
+++ b/src/ints/bios_disk.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: bios_disk.cpp,v 1.39 2009-08-12 21:16:09 c2woody Exp $ */
+/* $Id: bios_disk.cpp,v 1.40 2009-08-23 17:24:54 c2woody Exp $ */
 
 #include "dosbox.h"
 #include "callback.h"
@@ -309,6 +309,9 @@ static Bitu INT13_DiskHandler(void) {
 		if(imageDiskList[i]) any_images=true;
 	}
 
+	// unconditionally enable the interrupt flag
+	CALLBACK_SIF(true);
+
 	//drivenum = 0;
 	//LOG_MSG("INT13: Function %x called on drive %x (dos drive %d)", reg_ah,  reg_dl, drivenum);
 	switch(reg_ah) {