diff --git a/src/dos/dos_execute.cpp b/src/dos/dos_execute.cpp
index c089a06b..29ccb928 100644
--- a/src/dos/dos_execute.cpp
+++ b/src/dos/dos_execute.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: dos_execute.cpp,v 1.51 2005-10-17 20:17:08 c2woody Exp $ */
+/* $Id: dos_execute.cpp,v 1.52 2005-12-03 10:43:22 c2woody Exp $ */
 
 #include <string.h>
 #include <ctype.h>
@@ -274,6 +274,7 @@ bool DOS_Execute(char * name,PhysPt block_pt,Bit8u flags) {
 			if (imagesize+headersize<512) imagesize = 512-headersize;
 		}
 	}
+	Bit8u * loadbuf=(Bit8u *)new Bit8u[0x10000];
 	if (flags!=OVERLAY) {
 		/* Create an environment block */
 		envseg=block.exec.envseg;
@@ -285,6 +286,14 @@ bool DOS_Execute(char * name,PhysPt block_pt,Bit8u flags) {
 		Bit16u minsize,maxsize;Bit16u maxfree=0xffff;DOS_AllocateMemory(&pspseg,&maxfree);
 		if (iscom) {
 			minsize=0x1000;maxsize=0xffff;
+			if (machine==MCH_PCJR) {
+				/* try to load file into memory below 96k */ 
+				pos=0;DOS_SeekFile(fhandle,&pos,DOS_SEEK_SET);	
+				Bit16u dataread=0x1800;
+				DOS_ReadFile(fhandle,loadbuf,&dataread);
+				if (dataread<0x1800) maxsize=dataread;
+				if (minsize>maxsize) minsize=maxsize;
+			}
 		} else {	/* Exe size calculated from header */
 			minsize=long2para(imagesize+(head.minmemory<<4)+256);
 			if (head.maxmemory!=0) maxsize=long2para(imagesize+(head.maxmemory<<4)+256);
@@ -298,6 +307,11 @@ bool DOS_Execute(char * name,PhysPt block_pt,Bit8u flags) {
 		if (maxfree<maxsize) memsize=maxfree;
 		else memsize=maxsize;
 		if (!DOS_AllocateMemory(&pspseg,&memsize)) E_Exit("DOS:Exec error in memory");
+		if (iscom && (machine==MCH_PCJR) && (pspseg<0x2000)) {
+			maxsize=0xffff;
+			/* resize to full extent of memory block */
+			DOS_ResizeMemory(pspseg,&maxsize);
+		}
 		loadseg=pspseg+16;
 		if (!iscom) {
 			/* Check if requested to load program into upper part of allocated memory */
@@ -306,7 +320,6 @@ bool DOS_Execute(char * name,PhysPt block_pt,Bit8u flags) {
 		}
 	} else loadseg=block.overlay.loadseg;
 	/* Load the executable */
-	Bit8u * loadbuf=(Bit8u *)new Bit8u[0x10000];
 	loadaddress=PhysMake(loadseg,0);
 
 	if (iscom) {	/* COM Load 64k - 256 bytes max */
diff --git a/src/dos/dos_memory.cpp b/src/dos/dos_memory.cpp
index ed30d13b..ec4758a6 100644
--- a/src/dos/dos_memory.cpp
+++ b/src/dos/dos_memory.cpp
@@ -252,7 +252,7 @@ bool DOS_FreeMemory(Bit16u segment) {
 
 
 void DOS_BuildUMBChain(const char* use_umbs,bool ems_active) {
-	if (strcmp(use_umbs,"false")!=0) {
+	if ((strcmp(use_umbs,"false")!=0) && (machine!=MCH_TANDY)) {
 		Bit16u first_umb_seg=0xca00;
 		Bit16u first_umb_size=0x600;
 
@@ -365,7 +365,7 @@ static	CALLBACK_HandlerObject callbackhandler;
 void DOS_SetupMemory(void) {
 	// Create a dummy device MCB with PSPSeg=0x0008
 	DOS_MCB mcb_devicedummy((Bit16u)DOS_MEM_START);
-	mcb_devicedummy.SetPSPSeg(0x0008);	// Devices
+	mcb_devicedummy.SetPSPSeg(MCB_DOS);	// Devices
 	mcb_devicedummy.SetSize(1);
 	mcb_devicedummy.SetType(0x4d);		// More blocks will follow
 //	mcb_devicedummy.SetFileName("SD      ");
@@ -388,10 +388,31 @@ void DOS_SetupMemory(void) {
 
 	DOS_MCB mcb((Bit16u)DOS_MEM_START+2);
 	mcb.SetPSPSeg(MCB_FREE);						//Free
-	if (machine==MCH_TANDY) {
-		mcb.SetSize(0x97FE - DOS_MEM_START - 2);
-	} else mcb.SetSize(0x9FFE - DOS_MEM_START - 2);
 	mcb.SetType(0x5a);								//Last Block
+	if (machine==MCH_TANDY) {
+		/* memory up to 608k available, the rest (to 640k) is used by
+			the tandy graphics system's variable mapping of 0xb800 */
+		mcb.SetSize(0x97FE - DOS_MEM_START - 2);
+	} else if (machine==MCH_PCJR) {
+		/* memory from 128k to 640k is available */
+		mcb_devicedummy.SetPt((Bit16u)0x2000);
+		mcb_devicedummy.SetPSPSeg(MCB_FREE);
+		mcb_devicedummy.SetSize(0x9FFE - 0x2000);
+		mcb_devicedummy.SetType(0x5a);
+
+		/* exclude PCJr graphics region */
+		mcb_devicedummy.SetPt((Bit16u)0x17ff);
+		mcb_devicedummy.SetPSPSeg(MCB_DOS);
+		mcb_devicedummy.SetSize(0x800);
+		mcb_devicedummy.SetType(0x4d);
+
+		/* memory below 96k */
+		mcb.SetSize(0x1800 - DOS_MEM_START - 4);
+		mcb.SetType(0x4d);
+	} else {
+		/* complete memory up to 640k available */
+		mcb.SetSize(0x9FFE - DOS_MEM_START - 2);
+	}
 
 	dos.firstMCB=DOS_MEM_START;
 	dos_infoblock.SetFirstMCB(DOS_MEM_START);
diff --git a/src/hardware/memory.cpp b/src/hardware/memory.cpp
index 0d04ac66..8423c353 100644
--- a/src/hardware/memory.cpp
+++ b/src/hardware/memory.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: memory.cpp,v 1.39 2005-07-31 13:59:02 qbix79 Exp $ */
+/* $Id: memory.cpp,v 1.40 2005-12-03 10:43:22 c2woody Exp $ */
 
 #include "dosbox.h"
 #include "mem.h"
@@ -507,10 +507,16 @@ public:
 		for (i=0xc0;i<0xc8;i++) {
 			memory.phandlers[i] = &rom_page_handler;
 		}
-		/* Setup rom at 0xf0000-0x0x100000 */
+		/* Setup rom at 0xf0000-0x100000 */
 		for (i=0xf0;i<0x100;i++) {
 			memory.phandlers[i] = &rom_page_handler;
 		}
+		if (machine==MCH_PCJR) {
+			/* Setup cartridge rom at 0xe0000-0xf0000 */
+			for (i=0xe0;i<0xf0;i++) {
+				memory.phandlers[i] = &rom_page_handler;
+			}
+		}
 		/* Reset some links */
 		memory.links.used = 0;
 		// A20 Line - PS/2 system control port A
diff --git a/src/ints/ems.cpp b/src/ints/ems.cpp
index 94effec0..dade5702 100644
--- a/src/ints/ems.cpp
+++ b/src/ints/ems.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: ems.cpp,v 1.43 2005-09-03 11:38:18 c2woody Exp $ */
+/* $Id: ems.cpp,v 1.44 2005-12-03 10:43:22 c2woody Exp $ */
 
 #include <string.h>
 #include <stdlib.h>
@@ -1048,6 +1048,10 @@ public:
 		
 		Section_prop * section=static_cast<Section_prop *>(configuration);
 		if (!section->Get_bool("ems")) return;
+		if (machine==MCH_PCJR) {
+			LOG_MSG("EMS disabled for PCJr machine");
+			return;
+		}
 		BIOS_ZeroExtendedSize(true);
 		int67.Install(&INT67_Handler,CB_IRET,"Int 67 ems");
 		Bit16u call_int67=int67.Get_callback();