diff --git a/Source/HBIOS/cfg_dyno.asm b/Source/HBIOS/cfg_dyno.asm
index 76854aa0..ae48766a 100644
--- a/Source/HBIOS/cfg_dyno.asm
+++ b/Source/HBIOS/cfg_dyno.asm
@@ -193,4 +193,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_Z180	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_Z180	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_ezz80.asm b/Source/HBIOS/cfg_ezz80.asm
index d5c05616..1cf8073f 100644
--- a/Source/HBIOS/cfg_ezz80.asm
+++ b/Source/HBIOS/cfg_ezz80.asm
@@ -228,4 +228,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_master.asm b/Source/HBIOS/cfg_master.asm
index 9aa9f50d..e0571ca0 100644
--- a/Source/HBIOS/cfg_master.asm
+++ b/Source/HBIOS/cfg_master.asm
@@ -300,4 +300,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_mbc.asm b/Source/HBIOS/cfg_mbc.asm
index c5d10367..7fcd75b5 100644
--- a/Source/HBIOS/cfg_mbc.asm
+++ b/Source/HBIOS/cfg_mbc.asm
@@ -232,4 +232,4 @@ SPKENABLE	.EQU	TRUE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_MBC	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_mk4.asm b/Source/HBIOS/cfg_mk4.asm
index 2561adfb..17a76d84 100644
--- a/Source/HBIOS/cfg_mk4.asm
+++ b/Source/HBIOS/cfg_mk4.asm
@@ -233,4 +233,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_ECB	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_ECB	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_n8.asm b/Source/HBIOS/cfg_n8.asm
index 596e65a1..0f57a588 100644
--- a/Source/HBIOS/cfg_n8.asm
+++ b/Source/HBIOS/cfg_n8.asm
@@ -231,4 +231,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_ECB	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_ECB	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_rcz180.asm b/Source/HBIOS/cfg_rcz180.asm
index 8ba39dbb..27f08b6f 100644
--- a/Source/HBIOS/cfg_rcz180.asm
+++ b/Source/HBIOS/cfg_rcz180.asm
@@ -241,4 +241,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_Z180	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_Z180	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_rcz280.asm b/Source/HBIOS/cfg_rcz280.asm
index 0f212d6b..89d8b440 100644
--- a/Source/HBIOS/cfg_rcz280.asm
+++ b/Source/HBIOS/cfg_rcz280.asm
@@ -257,4 +257,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_Z280	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_Z280	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_rcz80.asm b/Source/HBIOS/cfg_rcz80.asm
index 0498e4f2..ee362ff8 100644
--- a/Source/HBIOS/cfg_rcz80.asm
+++ b/Source/HBIOS/cfg_rcz80.asm
@@ -246,4 +246,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_RC	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_RC	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_sbc.asm b/Source/HBIOS/cfg_sbc.asm
index 5e21ac26..83d5b9cc 100644
--- a/Source/HBIOS/cfg_sbc.asm
+++ b/Source/HBIOS/cfg_sbc.asm
@@ -232,4 +232,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_ECB	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_ECB	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_scz180.asm b/Source/HBIOS/cfg_scz180.asm
index 72c20acc..ebcb045a 100644
--- a/Source/HBIOS/cfg_scz180.asm
+++ b/Source/HBIOS/cfg_scz180.asm
@@ -236,4 +236,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_Z180	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_Z180	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_zeta.asm b/Source/HBIOS/cfg_zeta.asm
index 8b1aa2af..7a84a8e9 100644
--- a/Source/HBIOS/cfg_zeta.asm
+++ b/Source/HBIOS/cfg_zeta.asm
@@ -168,4 +168,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/cfg_zeta2.asm b/Source/HBIOS/cfg_zeta2.asm
index 7f71ec8a..c595edff 100644
--- a/Source/HBIOS/cfg_zeta2.asm
+++ b/Source/HBIOS/cfg_zeta2.asm
@@ -180,4 +180,4 @@ SPKENABLE	.EQU	FALSE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
 DMAENABLE	.EQU	FALSE		; DMA: ENABLE DMA DRIVER (DMA.ASM)
 DMABASE		.EQU	$E0		; DMA: DMA BASE ADDRESS
-DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC)
+DMAMODE		.EQU	DMAMODE_NONE	; DMA: DMA MODE (NONE|ECB|Z180|Z280|RC|MBC)
diff --git a/Source/HBIOS/dbgmon.asm b/Source/HBIOS/dbgmon.asm
index be3d5ca6..af3f28aa 100644
--- a/Source/HBIOS/dbgmon.asm
+++ b/Source/HBIOS/dbgmon.asm
@@ -33,6 +33,9 @@ BUFLEN	.EQU	40			; INPUT LINE LENGTH
 ;
 #IF DSKYENABLE
   #DEFINE USEDELAY
+ENA_XM	.SET	FALSE			; NO ROOM FOR BOTH DSKY+XMODEM
+#ELSE
+ENA_XM	.EQU	TRUE			; INCLUDE XMODEM IF SPACE AVAILABLE
 #ENDIF
 ;
 #INCLUDE "util.asm"
@@ -65,6 +68,7 @@ UART_ENTRY:
 ; P XXXX		- PROGRAM RAM STARTING AT XXXX, PROMPT FOR VALUES
 ; R XXXX		- RUN A PROGRAM AT ADDRESS XXXX
 ; S XX			- SET ACTIVE BANK TO XX
+; T xxxx 		- X-MODEM TRANSFER TO MEMORY LOCATION XXXX
 ; X			- EXIT MONITOR
 ;
 ;__COMMAND_PARSE______________________________________________________________
@@ -99,6 +103,10 @@ SERIALCMDLOOP:
 	JP	Z,PROGRM		; IF YES GO PROGRAM ROUTINE
 	CP	'O'			; IS IT AN "O" (Y/N)
 	JP	Z,POUT			; PORT OUTPUT
+#IF (ENA_XM)
+	CP	'T'			; IS IT A "T" (Y/N)
+	JP	Z,XMLOAD		; XMODEM TRANSFER
+#ENDIF
 	CP	'L'			; IS IT A "L" (Y/N)
 	JP	Z,HXLOAD		; INTEL HEX FORMAT LOAD DATA
 	CP	'I'			; IS IT AN "I" (Y/N)
@@ -317,6 +325,183 @@ KLOP1:
 	CALL	COUT			; OUTPUT KEY TO SCREEN
 	JR	KLOP1			; LOOP
 ;
+#IF (ENA_XM)
+;
+;__XMLOAD_____________________________________________________________________
+;
+;	LOAD A FILE INTO MEMORY FROM THE SERIAL PORT USING X-MODEM PROTOCOL
+;
+SOH:	.EQU	'A'-40h			; ^A CTRL-A
+EOT:	.EQU	'D'-40h			; ^D = End of Transmission
+ACK:	.EQU	'F'-40h			; ^F = Positive Acknowledgement
+NAK:	.EQU	'U'-40h			; ^U = Negative Acknowledgement
+CAN:	.EQU	'X'-40h			; ^X = Cancel
+;
+CPKTN	.DB	0			; CALCULATED PACKET NUMBER
+CPKTN1C	.DB	0			; CALCULATED PACKET NUMBER COMPLEMENT
+RETRYC	.DB	0			; RETRY COUNT
+RPKTN:	.DB	0			; RECEIVED PACKET NUMBER
+RPKTN1C:.DB	0			; RECEIVED PACKET NUMBER COMPLEMENT
+PKTCS	.DB	0 			; CHECKSUM
+;
+PSADDR:	.DW	0			; START OF PACKET ADDR
+;
+XMLOAD:	CALL	WORDPARM		; GET STARTING LOCATION
+	JP	C,ERR			; HANDLE SYNTAX ERRORS
+	PUSH	DE			; SAVE VALUE
+	CALL	NONBLANK		; LOOK FOR EXTRANEOUS PARAMETERS
+	CP	0			; TEST FOR TERMINATING NULL
+	JP	NZ,ERR			; ERROR IF NOT TERMINATING NULL
+;
+	LD	HL,TXT_READY		; READY FOR
+	CALL	PRTSTR			; TRANSFER
+	CALL	NEWLINE
+;
+	LD	BC,$F8F0		; GET CPU SPEED
+	RST	08			; AND MULTIPLY
+	LD	A,L			; BY 4
+	PUSH	AF
+	ADD	A,A			; TO CREATE
+	ADD	A,A			; TIMEOUT DELAY
+	LD	(TMOFCT),A		; FACTOR 
+	POP	AF
+;
+	LD	BC,$FE01		; SET FIRST NUMBER TO 1
+	LD	(CPKTN),BC		; ALSO STORE THE 1-COMPLEMENT
+;
+	POP	DE			; POINT TO WHERE TO SAVE THE PACKET
+	LD	(PSADDR),DE		; SAVE IF FOR THE CHECKSUM CALCULATION
+;
+GETNP:	LD	HL,RETRYC		; WE RETRY 20 TIMES BEFORE GIVING UP
+	LD 	(HL),20
+;
+NPLOOP:	LD 	B,6			; 6 SECONDS OF TIMEOUT BEFORE EACH NEW BLOCK
+	CALL	GCTO
+	JP 	NC,NOTOUT		; NO TIMEOUT ?
+;
+	DEC 	(HL)			; REACHED MAX NUMBER OF RETRIES?
+	JP 	Z,FAILRT		; YES, PRINT MESSAGE AND EXIT
+;
+	LD 	A,NAK			; SEND A NAK TO THE UPLOADER
+	CALL	COUT
+	JR 	NPLOOP			; LOOP UNTIL WE GET A GET A CHARACTOR OR TIMEOUT
+;
+NOTOUT:	CP	EOT			; DID UPLOADER SAY WE'RE FINISHED?
+	JP	Z,XMDONE		; YES, THEN WE'RE DONE
+	CP 	CAN			; UPLOADER WANTS TO FAIL TRANSFER?
+	JP 	Z,FAILCN		; YES, THEN WE'RE ALSO DONE
+	CP	SOH			; DID WE GET A START-OF-NEW-PACKET?
+	JR	NZ,NPLOOP		; NO, GO BACK AND TRY AGAIN
+;
+	LD	HL,RPKTN		; WE SAVE PACKET NUMBER HERE
+;
+	CALL	GCTO1			; WAIT ONE SECOND FOR A CHARACTER
+	LD	(HL),A                  ; SHOULD BE PACKET NUMBER
+	INC 	HL
+	JR	C,FAILTO		; TIMOUT ERROR?
+;
+	CALL	GCTO1			; WAIT ONE SECOND FOR A CHARACTER
+	LD	(HL),A			; SHOULD BE PACKET NUMBER COMPLEMENT
+	JR	C,FAILTO		; TIMOUT ERROR?
+
+	LD 	C,128			; GET 128 MORE CHARACTERS FOR A FULL PACKET
+PCKRCV:	CALL	GCTO1			; WAIT ONE SECOND FOR A CHARACTER
+	JR	C,FAILTO		; TIMOUT ERROR?
+	LD	(DE),A         		; SAVE THE RECEIVED CHAR
+	INC	DE
+	DEC	C	
+	JP	NZ,PCKRCV
+;
+	CALL	GCTO1			; WAIT ONE SECOND FOR A CHARACTER
+	JR	C,FAILTO		; TIMOUT ERROR?
+	LD	(PKTCS),A		; SHOULD BE CHECKSUM
+;
+	LD	HL,(PSADDR)		; CALCULATE CHECKSUM FROM 128 BYTES OF DATA
+	LD	B,128
+	XOR	A
+CSLOOP:	ADD	A,(HL)			; JUST ADD UP THE BYTES
+	INC	HL
+	DJNZ	CSLOOP
+;
+	LD	(PSADDR),DE		; SAVE THE NEW PACKET START ADDRESS
+;
+	LD	HL,PKTCS
+	XOR	(HL)			; HL POINTS TO THE RECEIVED CHECKSUM SO
+	JR	NZ,FAILCS		; BY XORING IT TO OUR SUM WE CHECK FOR EQUALITY
+;
+	LD	HL,(CPKTN)		; CHECK
+	LD	BC,(RPKTN)		; AGREEMENT
+;	XOR	A                       ; PACKET
+	SBC	HL,BC                   ; NUMBERS
+	JR	NZ,FAILPN
+;
+	LD	HL,CPKTN		; UPDATE THE PACKET COUNTERS
+	INC 	(HL)
+	INC	HL
+	DEC	(HL)
+;
+	LD 	A,ACK			; TELL UPLOADER THAT WE'RE HAPPY WITH WITH
+	CALL	COUT			; PACKET AND GO BACK AND FETCH SOME MORE
+	JP	GETNP
+;
+FAILRT:	LD	HL,TXT_RETRYERR		; FAILED ON RETRY
+	JR	XMERR
+FAILCN:	LD	HL,TXT_CANCLERR		; TRANSFER CANCELLED
+	JR	XMERR
+FAILCS:	LD	HL,TXT_CKSUMERR		; CHECKSUM ERROR 
+	JR	XMERR
+FAILPN:	LD	HL,TXT_PKNUMERR		; PACKET NUMBER ERROR
+	JR	XMERR
+FAILTO:	LD	HL,TXT_TMOUTERR		; TIMEOUT ERROR
+	JR	XMERR
+;
+XMDONE:	LD	A,ACK			; TELL REMOTE 
+	CALL	COUT			; WE'RE DONE
+	LD 	HL,TXT_LOADED		; TELL USER
+XMERR:	CALL	PRTSTR			; WE'RE DONE
+	JP	SERIALCMDLOOP		; BACK TO MENU
+;
+; WAITS FOR UP TO B SECONDS FOR A CHARACTER TO BECOME AVAILABLE AND
+; RETURNS IT IN A WITHOUT ECHO AND CARRY CLEAR. IF TIMEOUT THEN CARRY
+; IT SET.
+;
+; 4MHZ  20 SECONDS TMOFCT = 16
+; 10MHZ 20 SECONDS TMOFCT = 39
+;
+GCTO1:	LD	B,1			; WAIT 1 SECOND FOR SERIAL INPUT
+GCTO:	CALL	CST			; IF THERE IS A 
+	OR	A			; CHARACTER AVAILABLE
+	JR 	NZ,GETCHRX		; EXIT NOW OTHERWISE POLL
+GCTOA:	PUSH	BC
+	LD	BC,255			; C=CONSTANT (255) FOR INNER TIMING LOOP
+TMOFCT:	.EQU	$-1			; B=SPEED FACTOR WHICH GETS UPDATED AT START
+GCTOB:	PUSH	BC
+	LD	B,C
+GCTOC:	PUSH	BC
+	CALL	CST
+	OR	A			; A CHAR AVAILABLE?
+	JR 	NZ,GETCHR		; YES, GET OUT OF LOOP
+	POP	BC
+	DJNZ	GCTOC
+	POP	BC
+	DJNZ	GCTOB
+	POP	BC
+	DJNZ	GCTO
+	SCF 				; SET CARRY SIGNALS 
+	RET				; TIMEOUT OCCURRED
+GETCHR:	POP	BC
+	POP	BC
+	POP	BC
+GETCHRX:CALL	CIN			; GET THE CHARACTER
+	OR	A 			; CLEAR CARRY
+	RET				; SIGNALS SUCCESS
+
+TXT_PKNUMERR	.TEXT	"\r\nPacket Number Error$"
+TXT_TMOUTERR	.TEXT	"\r\nTimeout Error$"
+TXT_RETRYERR	.TEXT	"\r\nRetry Error$"
+TXT_CANCLERR	.TEXT	"\r\nTransfer Cancelled$"
+#ENDIF
+;
 ;__HXLOAD_____________________________________________________________________
 ;
 ;	LOAD INTEL HEX FORMAT FILE FROM THE SERIAL PORT, USER OPTION "H"
@@ -426,7 +611,8 @@ PIN:
 ;__DUMPMEM____________________________________________________________________
 ;
 ;	PRINT A MEMORY DUMP, USER OPTION "D"
-;	SYNTAX: D <START ADR> <END ADR>
+;	SYNTAX: D <START ADR> [END ADR]
+;	IF NO END ADDRESS, DUMP 100H BYTES
 ;_____________________________________________________________________________
 ;
 DUMPMEM:
@@ -434,12 +620,14 @@ DUMPMEM:
 	JP	C,ERR			; HANDLE ERRORS
 	PUSH	DE			; SAVE IT
 	CALL	WORDPARM		; GET END ADDRESS
-	JP	C,ERR			; HANDLE ERRORS
-	PUSH	DE			; SAVE IT
-
-	POP	DE			; DE := END ADDRESS
-	POP	HL			; HL := START ADDRESS
-
+	POP	HL			; RECOVER START
+	JR	NC,GDATA		; 
+;
+	LD	D,H			; DEFAULT TO 100H
+	LD	E,L			; BYTES IF NO
+	INC	D			; END ADDRESS
+	DEC	DE			; IS GIVEN
+;
 GDATA:
 	INC	DE			; BUMP DE FOR LATER COMPARE
 	CALL	NEWLINE			;
@@ -1006,7 +1194,7 @@ TXT_BADNUM	.TEXT	" *Invalid Hex Byte Value*$"
 TXT_MINIHELP	.TEXT	" (? for Help)$"
 TXT_HELP	.TEXT	"\r\nMonitor Commands (all values in hex):"
 		.TEXT	"\r\nB                - Boot system"
-		.TEXT	"\r\nD xxxx yyyy      - Dump memory from xxxx to yyyy"
+		.TEXT	"\r\nD xxxx [yyyy]    - Dump memory from xxxx to yyyy"
 		.TEXT	"\r\nF xxxx yyyy zz   - Fill memory from xxxx to yyyy with zz"
 		.TEXT	"\r\nH                - Halt system"
 		.TEXT	"\r\nI xxxx           - Input from port xxxx"
@@ -1018,6 +1206,9 @@ TXT_HELP	.TEXT	"\r\nMonitor Commands (all values in hex):"
 		.TEXT	"\r\nR xxxx [[yy] [zzzz]]  - Run code at address xxxx"
 		.TEXT	"\r\n                        Pass yy and zzzz to register A and BC"
 		.TEXT	"\r\nS xx             - Set bank to xx"
+#IF (ENA_XM)
+		.TEXT	"\r\nT xxxx           - X-modem transfer to memory location xxxx"
+#ENDIF
 		.TEXT	"\r\nX                - Exit monitor"
 		.TEXT	"$"
 ;
@@ -1592,6 +1783,7 @@ DSKY_ENTRY:
 #ENDIF
 ;
 ;
+		.FILL	16,0		; SET MINIMUM STACK DEPTH
 SLACK		.EQU	(MON_END - $)
 		.FILL	SLACK,00H
 ;
diff --git a/Source/HBIOS/dma.asm b/Source/HBIOS/dma.asm
index df255434..e8cf8153 100644
--- a/Source/HBIOS/dma.asm
+++ b/Source/HBIOS/dma.asm
@@ -1,11 +1,7 @@
 ;==================================================================================================
-; Z80 DMA DRIVER FOR ECB-DMA
+; Z80 DMA DRIVER
 ;==================================================================================================
 ;
-; DUE TO LOW CLOCK SPEED CONTRAINTS OF Z80 DMA CHIP, THE HALF CLOCK FACILITY 
-; IS USED DURING DMA PROGRAMMING AND CONTINUOUS BLOCK TRANSFERS.
-; TESTING CONDUCTED ON A SBC-V2-005 @ 10Mhz
-;
 DMA_CONTINUOUS			.equ 	%10111101	; + Pulse
 DMA_BYTE			.equ 	%10011101	; + Pulse
 DMA_BURST 			.equ	%11011101	; + Pulse
@@ -26,7 +22,19 @@ DMA_RESET			.equ	$c3
 ;DMA_ENABLE_AFTER_RETI		.equ	$b7
 ;DMA_REINIT_STATUS_BYTE		.equ	$8b
 ;
-DMA_FBACK			.equ	TRUE
+DMA_FBACK			.equ	TRUE	; ALLOW FALLBACK TO SOFTWARE
+DMA_USEHS			.equ	TRUE	; USE CLOCK DIVIDER
+;
+#IF (DMAMODE=DMAMODE_MBC)
+DMA_RDY				.EQU	%00000000
+DMA_FORCE			.EQU	1
+;DMA_USEHS			.SET	FALSE
+#ENDIF
+#IF (DMAMODE=DMAMODE_ECB)
+DMA_RDY				.EQU	%00001000
+DMA_FORCE			.EQU	0
+DMA_USEHS			.SET	TRUE
+#ENDIF
 ;
 ;==================================================================================================
 ; DMA INITIALIZATION CODE
@@ -38,12 +46,14 @@ DMA_INIT:
 	LD	A, DMABASE
 	CALL	PRTHEXBYTE
 ;
-	xor	a
+	LD	A,DMA_FORCE
 	out	(DMABASE+1),a		; force ready off
 ;
+#IF (DMA_USEHS)
 	ld	a,(HB_RTCVAL)
 	or	%00001000		; half
 	out	(RTCIO),a		; clock
+#ENDIF
 ;
 	call	DMAProbe		; do we have a dma?
 	jr	nz,DMA_NOTFOUND
@@ -58,11 +68,13 @@ DMA_INIT:
 	xor	a			; set status
 ;
 DMA_EXIT:
+#IF (DMA_USEHS)
 	push	af
 	ld	a,(HB_RTCVAL)
 	and	%11110111		; full
 	out	(RTCIO),a		; clock
 	pop	af
+#ENDIF
 	ret
 ;
 DMA_NOTFOUND:
@@ -132,7 +144,7 @@ DMACode		;.db	DMA_DISABLE	; R6-Command Disable DMA
 		.dw	0 		; R4-Port B, Destination address
 		.db	%00001100	; R4-Pulse byte follows, Pulse generated
 		.db	0		; R4-Pulse offset
-		.db	%10011010 	; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH
+		.db	%10010010+DMA_RDY; R5-Stop on end of block, ce/wait multiplexed, READY active config
 		.db	DMA_LOAD 	; R6-Command Load
 ;		.db	DMA_FORCE_READY	; R6-Command Force ready
 ;		.db	DMA_ENABLE 	; R6-Command Enable DMA
@@ -151,9 +163,11 @@ DMALDIR:
 	ld	b,DMACopy_Len		; dma command
 	ld	c,DMABASE		; block
 ;
+#IF (DMA_USEHS)
 	ld	a,(HB_RTCVAL)
 	or	%00001000		; half
 	out	(RTCIO),a		; clock
+#ENDIF
 	di
 	otir				; load and execute dma
 	ei
@@ -163,12 +177,13 @@ DMALDIR:
 	in	a,(DMABASE)		; set non-zero
 	and	%00111011		; if failed
 	sub	%00011011
-
+#IF (DMA_USEHS)
 	push	af
 	ld	a,(HB_RTCVAL)
 	and	%11110111		; full
 	out	(RTCIO),a		; clock
 	pop	af
+#ENDIF
 	ret
 ;
 DMACopy 	;.db	DMA_DISABLE	; R6-Command Disable DMA
@@ -182,7 +197,7 @@ DMALength	.dw	0 		; R0-Block length
 DMADest		.dw	0 		; R4-Port B, Destination address
 		.db	%00001100	; R4-Pulse byte follows, Pulse generated
 		.db	0		; R4-Pulse offset
-;		.db	%10011010 	; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH
+;		.db	%10010010+DMA_RDY;R5-Stop on end of block, ce/wait multiplexed, READY active config
 		.db	DMA_LOAD 	; R6-Command Load
 		.db	DMA_FORCE_READY	; R6-Command Force ready
 		.db	DMA_ENABLE 	; R6-Command Enable DMA
@@ -201,9 +216,11 @@ DMAOTIR:
 	ld	b,DMAOut_Len		; dma command
 	ld	c,DMABASE		; block
 ;
+#IF (DMA_USEHS)
 	ld	a,(HB_RTCVAL)
 	or	%00001000		; half
 	out	(RTCIO),a		; clock
+#ENDIF
 	di
 	otir				; load and execute dma
 	ei
@@ -214,11 +231,13 @@ DMAOTIR:
 	and	%00111011		; if failed
 	sub	%00011011
 ;
+#IF (DMA_USEHS)
 	push	af
 	ld	a,(HB_RTCVAL)
 	and	%11110111		; full
 	out	(RTCIO),a		; clock
 	pop	af
+#ENDIF
 	ret
 ;
 DMAOutCode  	;.db	DMA_DISABLE	; R6-Command Disable DMA
@@ -235,7 +254,7 @@ DMAOutDest	.db	0 		; R4-Port B, Destination port
 ;		.db	%00001100	; R4-Pulse byte follows, Pulse generated
 ;		.db	0		; R4-Pulse offset
 
-		.db	%10011010 	; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH	
+		.db	%10010010+DMA_RDY;R5-Stop on end of block, ce/wait multiplexed, READY active config	
 		.db	DMA_LOAD 	; R6-Command Load							
 		.db	%00000101	; R0-Port A is Source							
 		.db	DMA_LOAD 	; R6-Command Load							
@@ -256,9 +275,11 @@ DMAINIR:
 	ld	b,DMAIn_Len		; dma command
 	ld	c,DMABASE		; block
 ;
+#IF (DMA_USEHS)
 	ld	a,(HB_RTCVAL)
 	or	%00001000		; half
 	out	(RTCIO),a		; clock
+#ENDIF
 	di
 	otir				; load and execute dma
 	ei
@@ -269,11 +290,13 @@ DMAINIR:
 	and	%00111011		; if failed
 	sub	%00011011
 ;
+#IF (DMA_USEHS)
 	push	af
 	ld	a,(HB_RTCVAL)
 	and	%11110111		; full
 	out	(RTCIO),a		; clock
 	pop	af
+#ENDIF
 	ret
 ;
 DMAInCode 	;.db	DMA_DISABLE	; R6-Command Disable DMA
@@ -287,7 +310,7 @@ DMAInLength	.dw	0 		; R0-Block length
 DMAInSource	.db	0 		; R4-Port B, Destination port
 ;		.db	%00001100	; R4-Pulse byte follows, Pulse generated
 ;		.db	0		; R4-Pulse offset
-		.db	%10011010 	; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH	
+		.db	%10010010+DMA_RDY;R5-Stop on end of block, ce/wait multiplexed, READY active config	
 		.db	DMA_LOAD 	; R6-Command Load							
 		.db	DMA_FORCE_READY	; R6-Command Force ready						
 		.db	DMA_ENABLE 	; R6-Command Enable DMA							
@@ -295,7 +318,7 @@ DMAInSource	.db	0 		; R4-Port B, Destination port
 DMAIn_Len 	.equ	$-DMAInCode
 ;
 ;==================================================================================================
-; DEBUG - READ START, DESTINATION AN COUNT REGISTERS
+; DEBUG - READ START, DESTINATION AND COUNT REGISTERS
 ;==================================================================================================
 ;
 #IF (0)
diff --git a/Source/HBIOS/std.asm b/Source/HBIOS/std.asm
index 5c2ab4f7..c40f87de 100644
--- a/Source/HBIOS/std.asm
+++ b/Source/HBIOS/std.asm
@@ -225,6 +225,7 @@ DMAMODE_ECB	.EQU	1		; ECB-DMA WOLFGANG KABATZKE'S Z80 DMA ECB BOARD
 DMAMODE_Z180	.EQU	2		; Z180 INTEGRATED DMA
 DMAMODE_Z280	.EQU	3		; Z280 INTEGRATED DMA
 DMAMODE_RC	.EQU	4		; RC2014 Z80 DMA
+DMAMODE_MBC	.EQU	5		; MBC
 ;
 ; SERIAL DEVICE CONFIGURATION CONSTANTS
 ;
diff --git a/Source/HBIOS/uf.asm b/Source/HBIOS/uf.asm
index c0f04c63..049167c0 100644
--- a/Source/HBIOS/uf.asm
+++ b/Source/HBIOS/uf.asm
@@ -64,7 +64,7 @@ UF_INIT:
 	OR	A			; REQUIRES TERMINAL PROGRAM
 	RET	NZ			; TO HAVE INITIALIZED PORT
 	CALL	PRTSTRD			; ON PC SIDE.
-	.TEXT	" No connection$"
+	.TEXT	" NO CONNECTION$"
 	RET
 ;
 ; INPUT A CHARACTER AND RETURN IT IN E