diff --git a/Doc/ChangeLog.txt b/Doc/ChangeLog.txt
index 947ddb71..1ffeef76 100644
--- a/Doc/ChangeLog.txt
+++ b/Doc/ChangeLog.txt
@@ -19,6 +19,9 @@ Version 3.1.1
 - WBW: Add support Z80-512K (watchdog and LED)
 - WBW: Add support for ZZ80MB address map
 - PLS: Add support for Z180 invalid opcode trap
+- WBW: Add support for ZZRCC
+- WBW: Allow selection of RAM/ROM disk individually in build
+- WBW: Support 256KB ROM size
 
 Version 3.1
 -----------
diff --git a/Source/BPBIOS/diskdefs b/Source/BPBIOS/diskdefs
index db9ef4b2..c35156b3 100644
--- a/Source/BPBIOS/diskdefs
+++ b/Source/BPBIOS/diskdefs
@@ -271,6 +271,19 @@ diskdef interak
   os 2.2
 end
 
+# RomWBW 256KB ROM (128KB reserved, 128KB ROM Disk)
+
+diskdef wbw_rom256
+  seclen 512
+  tracks 4
+  sectrk 64
+  blocksize 2048
+  maxdir 256
+  skew 0
+  boottrk 0
+  os 2.2
+end
+
 # RomWBW 512KB ROM (128KB reserved, 384KB ROM Disk)
 
 diskdef wbw_rom512
diff --git a/Source/CBIOS/cbios.asm b/Source/CBIOS/cbios.asm
index 34d8647d..43a7d4c8 100644
--- a/Source/CBIOS/cbios.asm
+++ b/Source/CBIOS/cbios.asm
@@ -2166,6 +2166,37 @@ INIT2:
 	CALL	MD_INIT		; INITIALIZE MEMORY DISK DRIVER (RAM/ROM)
 	CALL	DRV_INIT	; INITIALIZE DRIVE MAP
 	CALL	DPH_INIT	; INITIALIZE DPH TABLE AND BUFFERS
+;
+	; SET THE DEFAULT DRIVE
+	XOR	A		; ZERO ACCUM
+	LD	(DEFDRIVE),A	; SET DEFAULT DRIVE TO A: TO START
+;
+#IFDEF PLTWBW
+;
+	; IF WE HAVE MULTIPLE DRIVES AND THE FIRST DRIVE IS RAM DRIVE
+	; THEN MAKE OUR DEFAULT STARTUP DRIVE THE SECOND DRIVE (B:)
+	LD	HL,(DRVMAPADR)	; POINT TO DRIVE MAP
+	DEC	HL		; BUMP BACK TO DRIVE COUNT
+	LD	A,(HL)		; GET IT
+	CP 	2		; COMPARE TO 2
+	JR	C,INIT2X	; IF LESS THAN 2, THEN DONE
+;
+	LD	B,BF_DIODEVICE	; HBIOS FUNC: REPORT DEVICE INFO
+	INC	HL		; POINT TO UNIT FIELD
+	LD	C,(HL)		; ... OF FIRST DRIVE
+	RST	08		; CALL HBIOS
+	LD	A,D		; DEVICE TYPE TO A
+	CP	DIODEV_MD	; MEMORY DISK DEVICE?
+	JR	NZ,INIT2X	; IF NOT, THEN DONE
+	LD	A,C		; GET ATTRIBUTES
+	CP	%00101000	; TYPE = RAM?
+	JR	NZ,INIT2X	; IF NOT THEN DONE
+	LD	A,1		; USE SECOND DRIVE AS DEFAULT
+	LD	(DEFDRIVE),A	; RECORD DEFAULT DRIVE
+;
+INIT2X:
+;
+#ENDIF
 ;
 #IFDEF PLTUNA
 	; USE A DEDICATED BUFFER FOR UNA PHYSICAL DISK I/O
@@ -2419,7 +2450,7 @@ MD_INIT4:
 	LD	BC,$01FB		; UNA FUNC = SET BANK
 	LD	DE,(BNKRAMD)		; FIRST BANK OF RAM DISK
 	CALL	$FFFD			; DO IT (RST 08 NOT SAFE HERE)
-
+;
 #IF (CLRRAMDISK == CLR_AUTO)
 	; CHECK FIRST 32 DIRECTORY ENTRIES.  IF ANY START WITH AN INVALID
 	; VALUE, INIT THE RAM DISK.  VALID ENTRIES ARE E5 (EMPTY ENTRY) OR
@@ -2444,15 +2475,15 @@ CLRRAM2:
 	LD	BC,$01FB		; UNA FUNC = SET BANK
 	LD	DE,(BNKUSER)		; SWITCH BACK TO EXEC BANK FOR WRITESTR
 	CALL	$FFFD			; DO IT (RST 08 NOT SAFE HERE)
-
+;
 	CALL	NEWLINE2		; FORMATTING
 	LD	DE,STR_INITRAMDISK	; RAM DISK INIT MESSAGE
 	CALL	WRITESTR		; DISPLAY IT
-
+;
 	LD	BC,$01FB		; UNA FUNC = SET BANK
 	LD	DE,(BNKRAMD)		; FIRST BANK OF RAM DISK
 	CALL	$FFFD			; DO IT (RST 08 NOT SAFE HERE)
-
+;
 	LD	HL,0			; SOURCE ADR FOR FILL
 	LD	BC,$2000		; LENGTH OF FILL IS 8K
 	LD	A,$E5			; FILL VALUE
@@ -2462,17 +2493,19 @@ CLRRAM3:
 	LD	DE,(BNKUSER)		; SWITCH BACK TO EXEC BANK
 	CALL	$FFFD			; DO IT (RST 08 NOT SAFE HERE)
 	EI				; RESUME INTERRUPTS
-
+;
 #ENDIF
-
+;
 #ELSE
 ;
 ; INITIALIZE RAM DISK BY FILLING DIRECTORY WITH 'E5' BYTES
 ; FILL FIRST 8K OF RAM DISK TRACK 1 WITH 'E5'
 ;
 #IF (CLRRAMDISK != CLR_NEVER)
-	DI				; NO INTERRUPTS
 	LD	A,(BNKRAMD)		; FIRST BANK OF RAM DISK
+	CP	$FF			; $FF SIGNIFIES NO RAM DISK
+	RET	Z			; BAIL OUT IF NO RAM DISK
+	DI				; NO INTERRUPTS
 	CALL	HB_BNKSEL		; SELECT BANK
 
 #IF (CLRRAMDISK == CLR_AUTO)
@@ -2679,14 +2712,14 @@ DRV_INIT:
 	; GET BOOT UNIT/SLICE INFO
 	LD	DE,(HCB + HCB_BOOTVOL)	; BOOT VOLUME (UNIT, SLICE)
 	LD	(BOOTVOL),DE		; D -> UNIT, E -> SLICE
-;
-	; INIT DEFAULT
-	LD	A,D			; BOOT UNIT?
-	CP	1			; IF ROM BOOT, DEF DRIVE SHOULD BE B:
-	JR	Z,DRV_INIT1		; ... SO LEAVE AS IS AND SKIP AHEAD
-	XOR	A			; ELSE FORCE TO DRIVE A:
-DRV_INIT1:
-	LD	(DEFDRIVE),A		; STORE IT
+;;
+;	; INIT DEFAULT
+;	LD	A,D			; BOOT UNIT?
+;	CP	1			; IF ROM BOOT, DEF DRIVE SHOULD BE B:
+;	JR	Z,DRV_INIT1		; ... SO LEAVE AS IS AND SKIP AHEAD
+;	XOR	A			; ELSE FORCE TO DRIVE A:
+;DRV_INIT1:
+;	LD	(DEFDRIVE),A		; STORE IT
 ;
 	; SETUP THE DRVMAP STRUCTURE
 	LD	HL,(HEAPTOP)		; GET CURRENT HEAP TOP
diff --git a/Source/CPM3/boot.z80 b/Source/CPM3/boot.z80
index 0b9c42f7..f94b2704 100644
--- a/Source/CPM3/boot.z80
+++ b/Source/CPM3/boot.z80
@@ -250,25 +250,6 @@ dinit6:
 	djnz	dinit6			; loop as needed
 	ret
 
-;	; zero out remaining dph table entries
-;	ld	a,16			; dph table entries
-;	sub	l			; subtract entries used
-;	ret	z			; return if all entries used
-;	ld	b,a			; save as loop counter
-;	ld	a,l			; current dph to accum
-;	rlca				; *2 for word entry
-;	ld	hl,@dtbl		; start of dtbl
-;	call	addhla			; hl now points to entry
-;	
-;dinit6a:
-;	xor	a			; zero accum
-;	ld	(hl),a			; zero lsb
-;	inc	hl			; next byte
-;	ld	(hl),a			; zero msb
-;	inc	hl			; next byte
-;	djnz	dinit6a
-;	ret				; finished
-
 dinit7:	; process a unit (all slices)
 	ld	e,0			; initialize slice index
 	ld	b,1			; default loop counter
@@ -518,10 +499,6 @@ time$get:
 	rst	08		; do it
 	ret	nz		; bail out on error
 	
-	ld	a,(datehack)
-	or	a
-	jr	nz,time$get1
-	
 	; convert yymmss in time buffer -> cpm3 epoch date offset
 	call	date2cpm	; time buf (yr, mon, day) -> SCB (@date)
 
@@ -540,24 +517,8 @@ time$set:
 	; CPM date/time in SCB -> RTC
 	
 	; convert CPM3 epoch date offset in SCB -> yymmss in time buffer
-	;call	cpm2date	; SCB (@date) -> time buf (yr, mon, day)
+	call	cpm2date	; SCB (@date) -> time buf (yr, mon, day)
 
-	; this is a temporary hack!!!
-	; since we cannot actually set the date on the RTC, we
-	; just read the current RTC date and use that so that we
-	; don't clobber a potentially good date.
-	; read time from RTC
-	ld	b,020h		; HBIOS func: get time
-	ld	hl,tim$buf	; time buffer
-	rst	08		; do it
-	ret	nz		; bail out on error
-	;
-	; now we set a hack active flag so that future time$get
-	; calls do not update the date field in the SCB
-	;
-	ld	a,0FFh		; true value
-	ld	(datehack),a	; save it
-	
 	; copy CPM3 time values from SCB -> time buffer
 	ld	a,(@hour)	; get hour from SCB
 	ld	(tim$hr),a	; ... and put in tim$hr
@@ -565,7 +526,7 @@ time$set:
 	ld	(tim$min),a     ; ... and put in tim$min
 	ld	a,(@sec)	; get second from SCB
 	ld	(tim$sec),a     ; ... and put in tim$sec
-	
+
 	; send time to RTC
 	ld	b,021h		; HBIOS func: set time
 	ld	hl,tim$buf	; ... from time buffer
@@ -577,7 +538,7 @@ date2cpm:
 	; Convert YYMMSS from time buffer at HL
 	; into offset from CPM epoch and store
 	; result in SCB.
-	
+
 	ld	hl,0		; initialize day counter
 	; Add in days for elapsed years
 	ld	a,(tim$yr)	; get current year
@@ -638,12 +599,75 @@ cpm2date:
 	; Convert CPM epoch date offset in SCB
 	; into YYMMSS values and store result in
 	; time buffer at HL.
-	ld	a,019h
-	ld	(tim$yr),a
-	ld	a,001h
-	ld	(tim$mon),a
-	ld	a,001h
-	ld	(tim$day),a
+
+	; We start by subtracting years keeping a count
+	; of the number of years.  Every fourth year is a leap
+	; year, so we account for that as we go.
+	ld	hl,(@date)	; get the count of days since epoch
+	dec	hl		; because we want 1/1/78 to be offset 0
+	ld	c,78		; init the years value
+c2d1:
+	ld	de,365		; normal number of days per year
+	ld	a,c
+	ld	b,0		; init leap year flag
+	and	03h		; check for leap year
+	jr	nz,c2d2		; if not zero, no need to adjust
+	inc	de		; add a day for leap year
+	ld	b,1		; leap year flag for later
+c2d2:
+	or	a		; clear carry
+	sbc	hl,de		; subtract
+	jr	c,c2d3		; get out if we went too far
+	inc	c		; add a year to year value
+	ld	a,c		; to accum
+	cp	100		; century rollover?
+	jr	nz,c2d1		; nope, loop
+	ld	c,0		; reset for start of century
+	jr	c2d1		; loop
+c2d3:
+	ld	a,c		; years to accum
+	call	bin2bcd		; convert to bcd
+	ld	(tim$yr),a	; ... and save it
+;
+	; Now we use the days per month table to find the
+	; month.
+	add	hl,de		; restore days remaining
+	ld	c,0		; init month value (zero offset)
+c2d4:
+	ld	a,c		; get month value
+	rlca			; times 2 for entry size
+	push	hl		; save hl (days remaining)
+	ld	hl,daysmon	; point to start of table
+	call	addhla		; point to month entry
+	ld	e,(hl)		; get count
+	inc	hl		; recover hl (days remaining)
+	ld	d,(hl)		; de := cum days at end of month
+	pop	hl
+	ld	a,c		; month value to accum
+	cp	1		; possible leap month?
+	jr	nz,c2d5		; no, leave alone
+	ld	a,b		; get leap year flag (set above)
+	or	a		; leap year?
+	jr	z,c2d5		; if not, skip ahead
+	inc	de		; account for leap year
+c2d5:
+	or	a		; clear carry
+	sbc	hl,de		; subtract days for the month
+	jr	c,c2d6		; get out if we went too far
+	inc	c		; next month
+	jr	c2d4		; continue
+c2d6:
+	inc	c		; switch from 0 to 1 offset
+	ld	a,c		; move to accum
+	call	bin2bcd		; convert to bcd
+	ld	(tim$mon),a	; save it
+;
+	; Leftover days is day value
+	add	hl,de		; restore days remaining
+	ld	a,l		; only need lsb
+	inc	a		; switch from 0 to 1 offset
+	call	bin2bcd		; convert to bcd
+	ld	(tim$day),a	; save it
 	
 	ret
 
@@ -662,6 +686,22 @@ daystbl:
 	dw	304		; November
 	dw	334		; December
 
+daysmon:
+	; days per month (non-leap year)
+	dw	31		; January
+	dw	28		; February (non-leap)
+	dw	31		; March
+	dw	30		; April
+	dw	31		; May
+	dw	30		; June
+	dw	31		; July
+	dw	31		; August
+	dw	30		; September
+	dw	31		; October
+	dw	30		; November
+	dw	31		; December
+	
+
 		; RTC time buffer (all values packed bcd)
 tim$buf:
 tim$yr		db	80h
@@ -671,8 +711,6 @@ tim$hr		db	01h
 tim$min		db	02h
 tim$sec		db	03h
 
-datehack	db	00h
-
 open:
 	ld	c,15
 	jp	bdos
diff --git a/Source/HBIOS/Build.ps1 b/Source/HBIOS/Build.ps1
index eb60585a..5f7fc69d 100644
--- a/Source/HBIOS/Build.ps1
+++ b/Source/HBIOS/Build.ps1
@@ -1,4 +1,4 @@
-param([string]$Platform = "", [string]$Config = "", [string]$RomSize = "512", [string]$RomName = "")
+param([string]$Platform = "", [string]$Config = "", [int]$RomSize = 512, [string]$RomName = "")
 
 #
 # This PowerShell script performs the heavy lifting in the build of RomWBW.  It handles the assembly
@@ -65,8 +65,8 @@ while ($true)
 #
 while ($true)
 {
-	if (($RomSize -eq "512") -or ($RomSize -eq "1024")) {break}
-	$RomSize = (Read-Host -prompt "ROM Size [512|1024]").Trim()
+	if (($RomSize -eq 128) -or ($RomSize -eq 256) -or ($RomSize -eq 512) -or ($RomSize -eq 1024)) {break}
+	$RomSize = (Read-Host -prompt "ROM Size [128|256|512|1024]").Trim()
 }
 
 #
@@ -114,7 +114,11 @@ $UpdFile = "${OutDir}/${RomName}.upd"	# Final name of System ROM image
 if ($Platform -eq "UNA") {$Bios = 'una'} else {$Bios = 'wbw'}
 
 # List of RomWBW proprietary apps to imbed in ROM disk.
-$RomApps = "assign","fdu","format","mode","rtc","survey","syscopy","sysgen","talk","timer","xm","inttest"
+$RomApps = "assign","mode","rtc","syscopy","xm"
+if ($RomSize -gt "256")
+{
+	$RomApps += "fdu","format","survey","sysgen","talk","timer","inttest"
+}
 
 ""
 "Building ${RomName} ${ROMSize}KB ROM configuration ${Config} for Z${CPUType}..."
@@ -211,27 +215,30 @@ if ($Platform -ne "UNA")
 # Create a blank ROM disk image to create a working ROM disk image
 Set-Content -Value ([byte[]](0xE5) * (([int]${RomSize} * 1KB) - 128KB)) -Encoding byte -Path $RomDiskFile
 
-# Copy all files from the appropriate directory to the working ROM disk image
-cpmcp -f $RomFmt $RomDiskFile ../RomDsk/ROM_${RomSize}KB/*.* 0:
-
-# Add any platform specific files to the working ROM disk image
-if (Test-Path "../RomDsk/${Platform}/*.*")
+if ($RomSize -gt 128)
 {
-	cpmcp -f $RomFmt $RomDiskFile ../RomDsk/${Platform}/*.* 0:
-}
+	# Copy all files from the appropriate directory to the working ROM disk image
+	cpmcp -f $RomFmt $RomDiskFile ../RomDsk/ROM_${RomSize}KB/*.* 0:
 
-# Add the proprietary RomWBW applications to the working ROM disk image
-foreach ($App in $RomApps)
-{
-	cpmcp -f $RomFmt $RomDiskFile ../../Binary/Apps/$App.com 0:
-}
+	# Add any platform specific files to the working ROM disk image
+	if (Test-Path "../RomDsk/${Platform}/*.*")
+	{
+		cpmcp -f $RomFmt $RomDiskFile ../RomDsk/${Platform}/*.* 0:
+	}
+	
+	# Add the proprietary RomWBW applications to the working ROM disk image
+	foreach ($App in $RomApps)
+	{
+		cpmcp -f $RomFmt $RomDiskFile ../../Binary/Apps/$App.com 0:
+	}
 
-# Add the CP/M and ZSystem system images to the ROM disk (used by SYSCOPY)
-cpmcp -f $RomFmt $RomDiskFile ..\cpm22\cpm_${Bios}.sys 0:cpm.sys
-cpmcp -f $RomFmt $RomDiskFile ..\zsdos\zsys_${Bios}.sys 0:zsys.sys
+	# Add the CP/M and ZSystem system images to the ROM disk (used by SYSCOPY)
+	cpmcp -f $RomFmt $RomDiskFile ..\cpm22\cpm_${Bios}.sys 0:cpm.sys
+	cpmcp -f $RomFmt $RomDiskFile ..\zsdos\zsys_${Bios}.sys 0:zsys.sys
 
-# Set all the files in the ROM disk image to read only for extra protection under flash file system.
-cpmchattr -f $RomFmt $RomDiskFile r 0:*.*
+	# Set all the files in the ROM disk image to read only for extra protection under flash file system.
+	cpmchattr -f $RomFmt $RomDiskFile r 0:*.*
+}
 
 #
 # Finally, the individual binary components are concatenated together to produce
diff --git a/Source/HBIOS/Build.sh b/Source/HBIOS/Build.sh
index e63a9510..6c351ae0 100755
--- a/Source/HBIOS/Build.sh
+++ b/Source/HBIOS/Build.sh
@@ -42,7 +42,7 @@ while ! echo ${configs[@]} | grep -s -w -q "$config" ; do
 done
 configfile=Config/${platform}_${config}.asm
 
-while [ ! '(' "$romsize" = 1024 -o "$romsize" = 512 ')' ] ; do
+while [ ! '(' "$romsize" = 1024 -o "$romsize" = 512 -o "$romsize" = 256 -o "$romsize" = 128 ')' ] ; do
 	echo -n "Romsize :"
 	read romsize
 done
@@ -58,7 +58,10 @@ else
 	BIOS=wbw
 fi
 
-Apps=(assign fdu format mode rtc survey syscopy sysgen talk timer xm inttest)
+Apps=(assign mode rtc syscopy xm)
+if [ $romsize -gt 256 ] ; then
+	Apps+=(fdu format survey sysgen talk timer inttest)
+fi
 
 blankfile=Blank${romsize}KB.dat
 romdiskfile=RomDisk.tmp
@@ -113,40 +116,43 @@ fi
 echo "Building ${romsize}KB $romname ROM disk data file..."
 
 cp $blankfile $romdiskfile
+	
+if [ $romsize -gt 128 ] ; then
 
-echo placing files into $romdiskfile
-
-for file in $(ls -1 ../RomDsk/ROM_${romsize}KB/* | sort -V) ; do
-	echo " " $file
-	$CPMCP -f $romfmt $romdiskfile $file 0:
-done
-
-if [ -d ../RomDsk/$platform ] ; then
-	for file in ../RomDsk/$platform/* ; do
+	echo placing files into $romdiskfile
+	
+	for file in $(ls -1 ../RomDsk/ROM_${romsize}KB/* | sort -V) ; do
 		echo " " $file
 		$CPMCP -f $romfmt $romdiskfile $file 0:
 	done
-fi
-
-echo "adding apps to $romdiskfile"
-for i in ${Apps[@]} ; do
-	set +e
-	f=$(../../Tools/unix/casefn.sh ../../Binary/Apps/$i.com)
-	set -e
-	if [ -z "$f" ] ; then
-		echo " " $i "not found"
-	else
-		echo " " $f
-		$CPMCP -f $romfmt $romdiskfile $f 0:
+	
+	if [ -d ../RomDsk/$platform ] ; then
+		for file in ../RomDsk/$platform/* ; do
+			echo " " $file
+			$CPMCP -f $romfmt $romdiskfile $file 0:
+		done
 	fi
-done
-
-echo "copying systems to $romdiskfile"
-$CPMCP -f $romfmt $romdiskfile ../CPM22/cpm_$BIOS.sys 0:cpm.sys
-$CPMCP -f $romfmt $romdiskfile ../ZSDOS/zsys_$BIOS.sys 0:zsys.sys
-
-echo "setting files in the ROM disk image to read only"
-$CPMCH -f $romfmt $romdiskfile  r 0:*.*
+	
+	echo "adding apps to $romdiskfile"
+	for i in ${Apps[@]} ; do
+		set +e
+		f=$(../../Tools/unix/casefn.sh ../../Binary/Apps/$i.com)
+		set -e
+		if [ -z "$f" ] ; then
+			echo " " $i "not found"
+		else
+			echo " " $f
+			$CPMCP -f $romfmt $romdiskfile $f 0:
+		fi
+	done
+	
+	echo "copying systems to $romdiskfile"
+	$CPMCP -f $romfmt $romdiskfile ../CPM22/cpm_$BIOS.sys 0:cpm.sys
+	$CPMCP -f $romfmt $romdiskfile ../ZSDOS/zsys_$BIOS.sys 0:zsys.sys
+	
+	echo "setting files in the ROM disk image to read only"
+	$CPMCH -f $romfmt $romdiskfile  r 0:*.*
+fi
 
 if [ $platform = UNA ] ; then
 	cp osimg.bin $outdir/UNA_WBW_SYS.bin
diff --git a/Source/HBIOS/Config/RCZ280_nat_zz.asm b/Source/HBIOS/Config/RCZ280_nat_zz.asm
index e74f9d28..d1ed2895 100644
--- a/Source/HBIOS/Config/RCZ280_nat_zz.asm
+++ b/Source/HBIOS/Config/RCZ280_nat_zz.asm
@@ -22,6 +22,8 @@
 ; PLEASE REFER TO THE CUSTOM BUILD INSTRUCTIONS (README.TXT) IN THE SOURCE DIRECTORY (TWO
 ; DIRECTORIES ABOVE THIS ONE).
 ;
+#DEFINE	PLATFORM_NAME	"ZZ80MB"
+;
 #DEFINE	BOOT_DEFAULT	"H"		; DEFAULT BOOT LOADER CMD ON <CR> OR AUTO BOOT
 ;
 #include "Config/RCZ280_nat.asm"
diff --git a/Source/HBIOS/Config/RCZ280_nat_zzr.asm b/Source/HBIOS/Config/RCZ280_nat_zzr.asm
new file mode 100644
index 00000000..ac12b876
--- /dev/null
+++ b/Source/HBIOS/Config/RCZ280_nat_zzr.asm
@@ -0,0 +1,44 @@
+;
+;==================================================================================================
+;   RC2014 Z280 STANDARD CONFIGURATION (NATIVE Z280 MMU W/ LINEAR MEMORY ON ZZRCC)
+;==================================================================================================
+;
+; THE COMPLETE SET OF DEFAULT CONFIGURATION SETTINGS FOR THIS PLATFORM ARE FOUND IN THE
+; CFG_<PLT>.ASM INCLUDED FILE WHICH IS FOUND IN THE PARENT DIRECTORY.  THIS FILE CONTAINS
+; COMMON CONFIGURATION SETTINGS THAT OVERRIDE THE DEFAULTS.  IT IS INTENDED THAT YOU MAKE
+; YOUR CUSTOMIZATIONS IN THIS FILE AND JUST INHERIT ALL OTHER SETTINGS FROM THE DEFAULTS.
+; EVEN BETTER, YOU CAN MAKE A COPY OF THIS FILE WITH A NAME LIKE <PLT>_XXX.ASM AND SPECIFY
+; YOUR FILE IN THE BUILD PROCESS.
+;
+; THE SETTINGS BELOW ARE THE SETTINGS THAT ARE MOST COMMONLY MODIFIED FOR THIS PLATFORM.
+; MANY OF THEM ARE EQUAL TO THE SETTINGS IN THE INCLUDED FILE, SO THEY DON'T REALLY DO
+; ANYTHING AS IS.  THEY ARE LISTED HERE TO MAKE IT EASY FOR YOU TO ADJUST THE MOST COMMON
+; SETTINGS.
+;
+; N.B., SINCE THE SETTINGS BELOW ARE REDEFINING VALUES ALREADY SET IN THE INCLUDED FILE,
+; TASM INSISTS THAT YOU USE THE .SET OPERATOR AND NOT THE .EQU OPERATOR BELOW. ATTEMPTING
+; TO REDEFINE A VALUE WITH .EQU BELOW WILL CAUSE TASM ERRORS!
+;
+; PLEASE REFER TO THE CUSTOM BUILD INSTRUCTIONS (README.TXT) IN THE SOURCE DIRECTORY (TWO
+; DIRECTORIES ABOVE THIS ONE).
+;
+#DEFINE	PLATFORM_NAME	"ZZRCC"
+;
+#DEFINE	BOOT_DEFAULT	"H"		; DEFAULT BOOT LOADER CMD ON <CR> OR AUTO BOOT
+;
+#include "Config/RCZ280_nat.asm"
+;
+;CPUOSC		.SET	29491200	; CPU OSC FREQ IN MHZ
+CPUOSC		.SET	24000000	; CPU OSC FREQ IN MHZ
+;
+RAMSIZE		.SET	384		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.SET	128		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.SET	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
+;
+RAMLOC		.SET	23		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
+RAMBIAS		.SET	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
+;
+MDROM		.SET	FALSE		; MD: ENABLE ROM DISK
+MDRAM		.SET	TRUE		; MD: ENABLE RAM DISK
+;
+Z2U0HFC		.SET	TRUE		; Z2U 0: ENABLE HARDWARE FLOW CONTROL
diff --git a/Source/HBIOS/Makefile b/Source/HBIOS/Makefile
index 117c4996..a5a480f8 100644
--- a/Source/HBIOS/Makefile
+++ b/Source/HBIOS/Makefile
@@ -15,6 +15,7 @@ else
 	OBJECTS += RCZ280_ext.rom RCZ280_ext.com RCZ280_ext.upd
 	OBJECTS += RCZ280_nat.rom RCZ280_nat.com RCZ280_nat.upd
 	OBJECTS += RCZ280_nat_zz.rom RCZ280_nat_zz.com RCZ280_nat_zz.upd
+	OBJECTS += RCZ280_nat_zzr.rom RCZ280_nat_zzr.com RCZ280_nat_zzr.upd
 	OBJECTS += RCZ80_kio.rom RCZ80_kio.com RCZ80_kio.upd
 	OBJECTS += RCZ80_mt.rom RCZ80_mt.com RCZ80_mt.upd
 	OBJECTS += RCZ80_duart.rom RCZ80_duart.com RCZ80_duart.upd
@@ -53,6 +54,7 @@ DIFFPATH = $(DIFFTO)/Binary
 ROMSIZE=512
 
 N8_std.rom: ROMSIZE=512
+RCZ280_nat_zzr.rom: ROMSIZE=256
 
 %.rom:
 	bash Build.sh $(DIFFBUILD) $(shell echo $* | sed 's/_/ /') $(ROMSIZE)
diff --git a/Source/HBIOS/cfg_dyno.asm b/Source/HBIOS/cfg_dyno.asm
index 6c513e3e..2ba312e0 100644
--- a/Source/HBIOS/cfg_dyno.asm
+++ b/Source/HBIOS/cfg_dyno.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	2		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_38400_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z180		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 RAMLOC		.EQU	19		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
 RAMBIAS		.EQU	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
@@ -107,6 +109,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_ezz80.asm b/Source/HBIOS/cfg_ezz80.asm
index e4559c0d..c8319829 100644
--- a/Source/HBIOS/cfg_ezz80.asm
+++ b/Source/HBIOS/cfg_ezz80.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	2		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_115200_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z2		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 MPGSEL_0	.EQU	$78		; Z2 MEM MGR BANK 0 PAGE SELECT REG (WRITE ONLY)
 MPGSEL_1	.EQU	$79		; Z2 MEM MGR BANK 1 PAGE SELECT REG (WRITE ONLY)
@@ -138,6 +140,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_master.asm b/Source/HBIOS/cfg_master.asm
index b202f09c..fa902178 100644
--- a/Source/HBIOS/cfg_master.asm
+++ b/Source/HBIOS/cfg_master.asm
@@ -25,7 +25,9 @@ INTMODE		.EQU	0		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_38400_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
-MEMMGR		.SET	MM_NONE		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
+MEMMGR		.EQU	MM_NONE		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 RAMLOC		.EQU	19		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
 RAMBIAS		.EQU	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
 MPCL_RAM	.EQU	$78		; SBC MEM MGR RAM PAGE SELECT REG (WRITE ONLY)
@@ -189,8 +191,10 @@ VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 VGASIZ		.EQU	V80X25		; VGA: DISPLAY FORMAT [V80X25|V80X30|V80X43]
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
-MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
+MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM
 ;
 FDENABLE	.EQU	FALSE		; FD: ENABLE FLOPPY DISK DRIVER (FD.ASM)
 FDMODE		.EQU	FDMODE_NONE	; FD: DRIVER MODE: FDMODE_[DIO|ZETA|ZETA2|DIDE|N8|DIO3|RCSMC|RCWDC|DYNO|EPWDC]
diff --git a/Source/HBIOS/cfg_mk4.asm b/Source/HBIOS/cfg_mk4.asm
index 32f611b3..4a05026f 100644
--- a/Source/HBIOS/cfg_mk4.asm
+++ b/Source/HBIOS/cfg_mk4.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	2		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_38400_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z180		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 RAMLOC		.EQU	19		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
 RAMBIAS		.EQU	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
@@ -125,6 +127,8 @@ VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 VGASIZ		.EQU	V80X25		; VGA: DISPLAY FORMAT [V80X25|V80X30|V80X43]
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_n8.asm b/Source/HBIOS/cfg_n8.asm
index 0e2e49b8..aaf967a1 100644
--- a/Source/HBIOS/cfg_n8.asm
+++ b/Source/HBIOS/cfg_n8.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	2		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_38400_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_N8		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 RAMBIAS		.EQU	0		; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
 RAMLOC		.EQU	0		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
@@ -128,6 +130,8 @@ VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 VGASIZ		.EQU	V80X25		; VGA: DISPLAY FORMAT [V80X25|V80X30|V80X43]
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_rcz180.asm b/Source/HBIOS/cfg_rcz180.asm
index 4e182511..5f9e9648 100644
--- a/Source/HBIOS/cfg_rcz180.asm
+++ b/Source/HBIOS/cfg_rcz180.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	2		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_115200_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z180		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 RAMLOC		.EQU	19		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
 RAMBIAS		.EQU	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
@@ -143,6 +145,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_rcz280.asm b/Source/HBIOS/cfg_rcz280.asm
index b2bbbe68..aa70891d 100644
--- a/Source/HBIOS/cfg_rcz280.asm
+++ b/Source/HBIOS/cfg_rcz280.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	0		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_115200_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z2		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 RAMLOC		.EQU	19		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
 RAMBIAS		.EQU	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
@@ -160,6 +162,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_rcz80.asm b/Source/HBIOS/cfg_rcz80.asm
index 88eb0531..45efe340 100644
--- a/Source/HBIOS/cfg_rcz80.asm
+++ b/Source/HBIOS/cfg_rcz80.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	1		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_115200_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z2		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 MPGSEL_0	.EQU	$78		; Z2 MEM MGR BANK 0 PAGE SELECT REG (WRITE ONLY)
 MPGSEL_1	.EQU	$79		; Z2 MEM MGR BANK 1 PAGE SELECT REG (WRITE ONLY)
@@ -150,6 +152,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_sbc.asm b/Source/HBIOS/cfg_sbc.asm
index fbdc125b..e3ec540e 100644
--- a/Source/HBIOS/cfg_sbc.asm
+++ b/Source/HBIOS/cfg_sbc.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	0		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_38400_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_SBC		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 MPCL_RAM	.EQU	$78		; SBC MEM MGR RAM PAGE SELECT REG (WRITE ONLY)
 MPCL_ROM	.EQU	$7C		; SBC MEM MGR ROM PAGE SELECT REG (WRITE ONLY)
@@ -128,6 +130,8 @@ VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 VGASIZ		.EQU	V80X25		; VGA: DISPLAY FORMAT [V80X25|V80X30|V80X43]
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_scz180.asm b/Source/HBIOS/cfg_scz180.asm
index 96c87a87..653e1c15 100644
--- a/Source/HBIOS/cfg_scz180.asm
+++ b/Source/HBIOS/cfg_scz180.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	2		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_115200_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z180		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 RAMLOC		.EQU	19		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
 RAMBIAS		.EQU	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
@@ -138,6 +140,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_una.asm b/Source/HBIOS/cfg_una.asm
index 10821319..b815f41b 100644
--- a/Source/HBIOS/cfg_una.asm
+++ b/Source/HBIOS/cfg_una.asm
@@ -22,6 +22,8 @@ CPUOSC		.EQU	18432000	; CPU OSC FREQ IN MHZ
 INTMODE		.EQU	0		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 ;
 RTCIO		.EQU	$70		; RTC LATCH REGISTER ADR
 ;
diff --git a/Source/HBIOS/cfg_zeta.asm b/Source/HBIOS/cfg_zeta.asm
index 1eda52df..6e1f0f33 100644
--- a/Source/HBIOS/cfg_zeta.asm
+++ b/Source/HBIOS/cfg_zeta.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	0		; INTERRUPT MODE: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_38400_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_SBC		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 MPCL_RAM	.EQU	$78		; SBC MEM MGR RAM PAGE SELECT REG (WRITE ONLY)
 MPCL_ROM	.EQU	$7C		; SBC MEM MGR ROM PAGE SELECT REG (WRITE ONLY)
@@ -103,6 +105,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/cfg_zeta2.asm b/Source/HBIOS/cfg_zeta2.asm
index 44783270..d010f660 100644
--- a/Source/HBIOS/cfg_zeta2.asm
+++ b/Source/HBIOS/cfg_zeta2.asm
@@ -28,6 +28,8 @@ INTMODE		.EQU	2		; INTERRUPTS: 0=NONE, 1=MODE 1, 2=MODE 2
 DEFSERCFG	.EQU	SER_38400_8N1	; DEFAULT SERIAL LINE CONFIG (SEE STD.ASM)
 ;
 RAMSIZE		.EQU	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+RAM_RESERVE	.EQU	0		; RESERVE FIRST N KB OF RAM (USUALLY 0)
+ROM_RESERVE	.EQU	0		; RESERVE FIRST N KB OR ROM (USUALLY 0)
 MEMMGR		.EQU	MM_Z2		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280]
 MPGSEL_0	.EQU	$78		; Z2 MEM MGR BANK 0 PAGE SELECT REG (WRITE ONLY)
 MPGSEL_1	.EQU	$79		; Z2 MEM MGR BANK 1 PAGE SELECT REG (WRITE ONLY)
@@ -114,6 +116,8 @@ TMSTIMENABLE	.EQU	FALSE		; TMS: ENABLE TIMER INTERRUPTS (REQUIRES IM1)
 VGAENABLE	.EQU	FALSE		; VGA: ENABLE VGA VIDEO/KBD DRIVER (VGA.ASM)
 ;
 MDENABLE	.EQU	TRUE		; MD: ENABLE MEMORY (ROM/RAM) DISK DRIVER (MD.ASM)
+MDROM		.EQU	TRUE		; MD: ENABLE ROM DISK
+MDRAM		.EQU	TRUE		; MD: ENABLE RAM DISK
 MDTRACE		.EQU	1		; MD: TRACE LEVEL (0=NO,1=ERRORS,2=ALL)
 MDFFENABLE	.EQU	FALSE		; MD: ENABLE FLASH FILE SYSTEM 
 ;
diff --git a/Source/HBIOS/diskdefs b/Source/HBIOS/diskdefs
index db9ef4b2..c35156b3 100644
--- a/Source/HBIOS/diskdefs
+++ b/Source/HBIOS/diskdefs
@@ -271,6 +271,19 @@ diskdef interak
   os 2.2
 end
 
+# RomWBW 256KB ROM (128KB reserved, 128KB ROM Disk)
+
+diskdef wbw_rom256
+  seclen 512
+  tracks 4
+  sectrk 64
+  blocksize 2048
+  maxdir 256
+  skew 0
+  boottrk 0
+  os 2.2
+end
+
 # RomWBW 512KB ROM (128KB reserved, 384KB ROM Disk)
 
 diskdef wbw_rom512
diff --git a/Source/HBIOS/game.asm b/Source/HBIOS/game.asm
index 43d90b87..66a618a7 100644
--- a/Source/HBIOS/game.asm
+++ b/Source/HBIOS/game.asm
@@ -1182,10 +1182,12 @@ PRTSTR:
 COUT:	PUSH	AF
 	PUSH	BC
 	PUSH	DE
+	PUSH	HL
 	LD	B,01H
 	LD	C,0
 	LD	E,A
 	RST	08
+	POP	HL
 	POP	DE
 	POP	BC
 	POP	AF
@@ -1202,10 +1204,14 @@ COUTE:	PUSH	AF
 ; WAIT FOR A CHARACTER FROM THE CONSOLE DEVICE AND RETURN IT IN A
 ;
 CIN:	PUSH	BC
+	PUSH	DE
+	PUSH	HL
 	LD	B,00H
 	LD	C,00H
 	RST	08
 	LD	A,E
+	POP	HL
+	POP	DE
 	POP	BC
 	RET
 
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 5430fdc5..c3e54fcd 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -666,6 +666,30 @@ HBX_PPRET:
 HBX_PPSP	.EQU	$ - 2
 	RET
 ;
+; SPECIAL ROUTINE IN HIGH MEMORY TO PERFORM A COLD START ON Z280
+; THIS REQUIRES US TO REMAP LOW MEMORY, THEN JUMP TO ZERO
+;
+#IF (MEMMGR == MM_Z280)
+;
+Z280_RESTART:
+	DI				; KILL INTERRUPTS
+	LD	SP,HBX_LOC		; STACK IN HIGH MEMORY
+;
+	; COPY Z280 BANK SELECT ROUTINE TO HIGH MEMORY
+	LD	HL,Z280_BNKSEL
+	LD	DE,$8000
+	LD	BC,Z280_BNKSEL_LEN
+	LDIR
+;
+	; MAKE ROM BOOT BANK ACTIVE IN LOW SYS MEM
+	LD	A,BID_BOOT
+	LD	B,$10			; FIRST SYS PDR
+	CALL	$8000			; DO IT
+;
+	; NOW JUST JUMP TO START OF ROM BOOT CODE
+	JP	0
+#ENDIF
+;
 ; PRIVATE STACK AT END OF HBIOS CODE
 ; OCCUPIES SPACE BEFORE IVT
 ;
@@ -2178,6 +2202,9 @@ HB_PCINITTBL:
 #IF (ASCIENABLE)
 	.DW	ASCI_PREINIT
 #ENDIF
+#IF (Z2UENABLE)
+	.DW	Z2U_PREINIT
+#ENDIF
 #IF (UARTENABLE)
 	.DW	UART_PREINIT
 #ENDIF
@@ -2190,9 +2217,6 @@ HB_PCINITTBL:
 #IF (ACIAENABLE)
 	.DW	ACIA_PREINIT
 #ENDIF
-#IF (Z2UENABLE)
-	.DW	Z2U_PREINIT
-#ENDIF
 #IF (PIO_4P | PIO_ZP)
 	.DW	PIO_PREINIT
 #ENDIF
@@ -2224,6 +2248,9 @@ HB_INITTBL:
 #IF (ASCIENABLE)
 	.DW	ASCI_INIT
 #ENDIF
+#IF (Z2UENABLE)
+	.DW	Z2U_INIT
+#ENDIF
 #IF (UARTENABLE)
 	.DW	UART_INIT
 #ENDIF
@@ -2236,9 +2263,6 @@ HB_INITTBL:
 #IF (ACIAENABLE)
 	.DW	ACIA_INIT
 #ENDIF
-#IF (Z2UENABLE)
-	.DW	Z2U_INIT
-#ENDIF
 #IF (DSRTCENABLE)
 	.DW	DSRTC_INIT
 #ENDIF
@@ -2944,11 +2968,15 @@ SYS_RESWARM:
 ; RESTART SYSTEM AS THOUGH POWER HAD JUST BEEN TURNED ON
 ;
 SYS_RESCOLD:
+#IF (MEMMGR == MM_Z280)
+	JP	Z280_RESTART
+#ELSE
 	DI
 	LD	SP,HBX_LOC		; STACK JUST BELOW HBIOS PROXY
 	LD	A,BID_BOOT		; BOOT BANK
 	LD	IX,0			; ADDRESS ZERO
 	CALL	HB_BNKCALL		; DOES NOT RETURN
+#ENDIF
 ;
 ; HOOK CALLED WHEN A USERLAND RESET IS INVOKED, TYPICALLY VIA A JUMP
 ; TO LOGICAL CPU ADDRESS $0000
@@ -4193,8 +4221,11 @@ Z280_IVT:
 ; REG A HAS BANK ID, REG B HAS INITIAL PDR TO PROGRAM
 ; REGISTERS AF, BC, HL DESTROYED
 ;
+; THIS ROUTINE MAY BE RELOCATED TO RUN IN HIGH MEMORY IN CERTAIN CASES
+; LIKE A SYSTEM RESTART.  IT MUST BE KEPT ENTIRELY RELOCATABLE.
+;
 Z280_BNKSEL:
-	; *DEBUG*
+	;; *DEBUG*
 	;CALL	PC_LBKT
 	;CALL	PRTHEXBYTE
 	;CALL	PC_RBKT
@@ -4259,6 +4290,9 @@ Z280_BNKSEL3:
 	LDCTL	(C),HL
 ;
 	RET
+;
+Z280_BNKSEL_LEN	.EQU	$ - Z280_BNKSEL
+;
 #ENDIF
 ;
 ; Z280 BANK COPY (CALLED FROM PROXY)
diff --git a/Source/HBIOS/md.asm b/Source/HBIOS/md.asm
index eb4c2446..b6c2d8eb 100644
--- a/Source/HBIOS/md.asm
+++ b/Source/HBIOS/md.asm
@@ -12,7 +12,7 @@
 ;	0x00 MEMORY DISK	0x01 ROM DRIVE		%00100000 HD STYLE, NON-REMOVABLE, TYPE-ROM
 ;	0x00 MEMORY DISK	0x01 ROM DRIVE		%00111000 HD STYLE, NON-REMOVABLE, TYPE-FLASH
 ;
-MD_DEVCNT	.EQU	2		; NUMBER OF MD DEVICES SUPPORTED
+;MD_DEVCNT	.EQU	2		; NUMBER OF MD DEVICES SUPPORTED
 MD_CFGSIZ	.EQU	8		; SIZE OF CFG TBL ENTRIES
 ;
 MD_DEV		.EQU	0		; OFFSET OF DEVICE NUMBER (BYTE)
@@ -32,18 +32,25 @@ MD_FVAR		.EQU	1		; FLASH VERIFY AFTER WRITE
 ; DEVICE CONFIG TABLE (RAM DEVICE FIRST TO MAKE IT ALWAYS FIRST DRIVE)
 ;
 MD_CFGTBL:
+#IF (MDRAM)
 	; DEVICE 1 (RAM)
 	.DB	1			; DRIVER DEVICE NUMBER
 	.DB	0			; DEVICE STATUS
 	.DW	0,0			; CURRENT LBA
 	.DB	MID_MDRAM		; DEVICE MEDIA ID
 	.DB	MD_ARAM			; DEVICE ATTRIBUTE
+#ENDIF
+;
+#IF (MDROM)
 	; DEVICE 0 (ROM)
 	.DB	0			; DEVICE NUMBER
 	.DB	0			; DEVICE STATUS
 	.DW	0,0			; CURRENT LBA
 	.DB	MID_MDROM		; DEVICE MEDIA ID
 	.DB	MD_AROM			; DEVICE ATTRIBUTE
+#ENDIF
+;
+MD_DEVCNT	.EQU	($ - MD_CFGTBL) / MD_CFGSIZ
 ;
 #IF ($ - MD_CFGTBL) != (MD_DEVCNT * MD_CFGSIZ)
 	.ECHO	"*** INVALID MD CONFIG TABLE ***\n"
@@ -59,35 +66,54 @@ MD_INIT:
 #ENDIF
 
 	CALL	NEWLINE			; FORMATTING
-	PRTS("MD: UNITS=2 $")
-	PRTS("ROMDISK=$")
+	PRTS("MD: UNITS=$")
+	LD	A,MD_DEVCNT
+	CALL	PRTDECB
+;
+#IF (MDROM)
+	PRTS(" ROMDISK=$")
 	LD	HL,ROMSIZE - 128
 	CALL	PRTDEC
-	PRTS("KB RAMDISK=$")
+	PRTS("KB$")
+#ENDIF
+;
+#IF (MDRAM)
+	PRTS(" RAMDISK=$")
 	LD	HL,RAMSIZE - 256
 	CALL	PRTDEC
 	PRTS("KB$")
+#ENDIF
 ;
 ; SETUP THE DIO TABLE ENTRIES
 ;
-#IF (MDFFENABLE)
+#IF (MDROM & MDFFENABLE)
 	LD	A,(MD_FFSEN)		; IF FLASH 
 	OR	A			; FILESYSTEM 
-	JR	NZ,MD_IN1		; CAPABLE, 
+	JR	NZ,MD_INIT1		; CAPABLE, 
 	LD	A,MD_AFSH		; UPDATE ROM DIO
 	LD	(MD_CFGTBL + MD_CFGSIZ + MD_ATTRIB),A
-MD_IN1:
+MD_INIT1:
 #ENDIF
-	LD	BC,MD_FNTBL
+;
 	LD	DE,MD_CFGTBL
-	PUSH	BC
-	CALL	DIO_ADDENT		; ADD FIRST ENTRY
-	POP	BC
-	LD	DE,MD_CFGTBL + MD_CFGSIZ
-	CALL	DIO_ADDENT		; ADD SECOND ENTRY
-
-	XOR	A			; INIT SUCCEEDED
-	RET				; RETURN
+;
+MD_INIT2:
+	LD	A,(DE)			; FIRST BYTE OF CONFIG
+	CP	$FF			; END OF TABLE?
+	JR	NZ,MD_INIT3		; IF NOT END OF TABLE, CONTINUE
+	XOR	A			; SIGNAL SUCCESS
+	RET				; AND RETURN
+;
+MD_INIT3:
+	LD	BC,MD_FNTBL		; BC IS FUNT TBL
+	PUSH	DE			; SAVE CFG PTR
+	CALL	DIO_ADDENT		; ADD DIO TBL ENTRY
+	POP	DE			; RECOVER CFG PTR
+	EX	DE,HL			; CFG PTR TO HL
+	LD	BC,MD_CFGSIZ		; ENTRY SIZ TO BC
+	ADD	HL,BC			; BUMP TO NEXT ENTRY
+	EX	DE,HL			; CFG PTR BACK TO DE
+	JR	MD_INIT2		; REPEAT
 ;
 ;
 ;
diff --git a/Source/HBIOS/std.asm b/Source/HBIOS/std.asm
index b4f0fe6b..25131225 100644
--- a/Source/HBIOS/std.asm
+++ b/Source/HBIOS/std.asm
@@ -454,21 +454,19 @@ SYSTIM	.SET	TM_Z280
 ; MEMORY BANK CONFIGURATION
 ;
 #IF (BIOS == BIOS_UNA)
-BID_ROM0	.EQU	$0000
-BID_RAM0	.EQU	$8000
+BID_ROM0	.EQU	$0000 + (ROM_RESERVE / 32)
+BID_RAM0	.EQU	$8000 + (RAM_RESERVE / 32)
 #ENDIF
 ;
 #IF (BIOS == BIOS_WBW)
-BID_ROM0	.EQU	$00
-BID_RAM0	.EQU	$80
+BID_ROM0	.EQU	$00 + (ROM_RESERVE / 32)
+BID_RAM0	.EQU	$80 + (RAM_RESERVE / 32)
 #ENDIF
 
 BID_ROMN	.EQU	(BID_ROM0 + ((ROMSIZE / 32) - 1))
 BID_RAMN	.EQU	(BID_RAM0 + ((RAMSIZE / 32) - 1))
 
 BID_BOOT	.EQU	BID_ROM0	; BOOT BANK
-;BID_BIOSIMG	.EQU	BID_ROM0 + 1	; BIOS IMAGE BANK
-;BID_OSIMG	.EQU	BID_ROM0 + 2	; ROM LOADER AND IMAGES BANK
 BID_IMG0	.EQU	BID_ROM0 + 1	; ROM LOADER AND FIRST IMAGES BANK
 BID_IMG1	.EQU	BID_ROM0 + 2	; SECOND IMAGES BANK
 BID_FSFAT	.EQU	BID_ROM0 + 3	; FAT FILESYSTEM DRIVER BANK
diff --git a/Source/HBIOS/usrrom.asm b/Source/HBIOS/usrrom.asm
index ead329be..908f0b93 100644
--- a/Source/HBIOS/usrrom.asm
+++ b/Source/HBIOS/usrrom.asm
@@ -7,10 +7,12 @@ CR	.EQU    0DH
 LF	.EQU    0AH
 ;
 	.ORG    USR_LOC
-;           
+;
+	LD	SP,USR_END
+;
 	LD	HL,BOOTMSG		; INTRODUCTION
 	CALL	PRTSTR
-
+;
 	CALL	CIN			; DO STUFF
 ;
 	LD	B,BF_SYSRESET		; SYSTEM RESTART
@@ -40,10 +42,13 @@ PRTSTR:	LD	A,(HL)
 COUT:	PUSH	AF
 	PUSH	BC
 	PUSH	DE
+	PUSH	HL
 	LD	B,01H
 	LD	C,0
 	LD	E,A
 	RST	08
+	CALL	$FFF0
+	POP	HL
 	POP	DE
 	POP	BC
 	POP	AF
@@ -60,10 +65,14 @@ COUTE:	PUSH	AF
 ; WAIT FOR A CHARACTER FROM THE CONSOLE DEVICE AND RETURN IT IN A
 ;
 CIN:	PUSH	BC
+	PUSH	DE
+	PUSH	HL
 	LD	B,00H
 	LD	C,00H
 	RST	08
 	LD	A,E
+	POP	HL
+	POP	DE
 	POP	BC
 	RET
 ;
diff --git a/Source/Images/diskdefs b/Source/Images/diskdefs
index db9ef4b2..c35156b3 100644
--- a/Source/Images/diskdefs
+++ b/Source/Images/diskdefs
@@ -271,6 +271,19 @@ diskdef interak
   os 2.2
 end
 
+# RomWBW 256KB ROM (128KB reserved, 128KB ROM Disk)
+
+diskdef wbw_rom256
+  seclen 512
+  tracks 4
+  sectrk 64
+  blocksize 2048
+  maxdir 256
+  skew 0
+  boottrk 0
+  os 2.2
+end
+
 # RomWBW 512KB ROM (128KB reserved, 384KB ROM Disk)
 
 diskdef wbw_rom512
diff --git a/Source/Images/hd1024_prefix.dat b/Source/Images/hd1024_prefix.dat
index 1ec28fa1..f4f1aa3b 100644
Binary files a/Source/Images/hd1024_prefix.dat and b/Source/Images/hd1024_prefix.dat differ
diff --git a/Source/RomDsk/ROM_256KB/ASM.COM b/Source/RomDsk/ROM_256KB/ASM.COM
new file mode 100644
index 00000000..a63e5aec
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/ASM.COM differ
diff --git a/Source/RomDsk/ROM_256KB/CLRDIR.COM b/Source/RomDsk/ROM_256KB/CLRDIR.COM
new file mode 100644
index 00000000..ca65cbed
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/CLRDIR.COM differ
diff --git a/Source/RomDsk/ROM_256KB/DDT.COM b/Source/RomDsk/ROM_256KB/DDT.COM
new file mode 100644
index 00000000..70e4ebfe
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/DDT.COM differ
diff --git a/Source/RomDsk/ROM_256KB/DDTZ.COM b/Source/RomDsk/ROM_256KB/DDTZ.COM
new file mode 100644
index 00000000..4f6eca6b
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/DDTZ.COM differ
diff --git a/Source/RomDsk/ROM_256KB/DUMP.COM b/Source/RomDsk/ROM_256KB/DUMP.COM
new file mode 100644
index 00000000..03a77c3c
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/DUMP.COM differ
diff --git a/Source/RomDsk/ROM_256KB/ED.COM b/Source/RomDsk/ROM_256KB/ED.COM
new file mode 100644
index 00000000..a0f0f541
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/ED.COM differ
diff --git a/Source/RomDsk/ROM_256KB/FLASH.COM b/Source/RomDsk/ROM_256KB/FLASH.COM
new file mode 100644
index 00000000..c81f9c54
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/FLASH.COM differ
diff --git a/Source/RomDsk/ROM_256KB/LOAD.COM b/Source/RomDsk/ROM_256KB/LOAD.COM
new file mode 100644
index 00000000..b9601e00
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/LOAD.COM differ
diff --git a/Source/RomDsk/ROM_256KB/PIP.COM b/Source/RomDsk/ROM_256KB/PIP.COM
new file mode 100644
index 00000000..4b2ce4b6
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/PIP.COM differ
diff --git a/Source/RomDsk/ROM_256KB/RELOG.COM b/Source/RomDsk/ROM_256KB/RELOG.COM
new file mode 100644
index 00000000..13ffc62e
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/RELOG.COM differ
diff --git a/Source/RomDsk/ROM_256KB/STAT.COM b/Source/RomDsk/ROM_256KB/STAT.COM
new file mode 100644
index 00000000..1de359f2
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/STAT.COM differ
diff --git a/Source/RomDsk/ROM_256KB/SUBMIT.COM b/Source/RomDsk/ROM_256KB/SUBMIT.COM
new file mode 100644
index 00000000..f651bfee
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/SUBMIT.COM differ
diff --git a/Source/RomDsk/ROM_256KB/XSUB.COM b/Source/RomDsk/ROM_256KB/XSUB.COM
new file mode 100644
index 00000000..15e86abf
Binary files /dev/null and b/Source/RomDsk/ROM_256KB/XSUB.COM differ
diff --git a/Source/ZRC/ZRC Disk Layout.txt b/Source/ZRC/ZRC Disk Layout.txt
index 7f8e3975..d8a6e027 100644
--- a/Source/ZRC/ZRC Disk Layout.txt	
+++ b/Source/ZRC/ZRC Disk Layout.txt	
@@ -13,4 +13,12 @@ Start	Length	Description
 0x20000 0x04000	Filler
 0x24000 0x80000	RomWBW
 0xA4000 0x5C000	Filler
-0x100000: Start of slices (partition 0x1E)
\ No newline at end of file
+0x100000: Start of slices (partition 0x1E)
+
+Notes
+-----
+
+- At startup CPLD ROM is mapped to Z80 CPU address space 0x0000-0x003F, CPU begins execution at 0x0000
+- CPLD ROM (CF bootstrap mode) reads CF Boot Loader (256B) from start of CF (MBR) to 0xB000 and runs it
+- CF Boot Loader reads ZRC Monitor (4KB) from sectors 0xF8-0xFF of CF to 0xB400 and runs it
+- ZRC Monitor reads 512KB (RomWBW) from sectors 0x120-0x51F of CF into first 512KB of RAM
diff --git a/Source/ZRC/zrc_ptbl.bin b/Source/ZRC/zrc_ptbl.bin
index ca19be4c..5e3a2a4d 100644
Binary files a/Source/ZRC/zrc_ptbl.bin and b/Source/ZRC/zrc_ptbl.bin differ
diff --git a/Source/ver.inc b/Source/ver.inc
index 0e2b5687..4778cc06 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,4 +2,4 @@
 #DEFINE	RMN	1
 #DEFINE	RUP	1
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.1.1-pre.55"
+#DEFINE BIOSVER	"3.1.1-pre.59"
diff --git a/Source/ver.lib b/Source/ver.lib
index 8e71dfa2..a3b67e1d 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	1
 rup	equ	1
 rtp	equ	0
 biosver	macro
-	db	"3.1.1-pre.55"
+	db	"3.1.1-pre.59"
 	endm
diff --git a/Tools/cpmtools/diskdefs b/Tools/cpmtools/diskdefs
index db9ef4b2..c35156b3 100644
--- a/Tools/cpmtools/diskdefs
+++ b/Tools/cpmtools/diskdefs
@@ -271,6 +271,19 @@ diskdef interak
   os 2.2
 end
 
+# RomWBW 256KB ROM (128KB reserved, 128KB ROM Disk)
+
+diskdef wbw_rom256
+  seclen 512
+  tracks 4
+  sectrk 64
+  blocksize 2048
+  maxdir 256
+  skew 0
+  boottrk 0
+  os 2.2
+end
+
 # RomWBW 512KB ROM (128KB reserved, 384KB ROM Disk)
 
 diskdef wbw_rom512