diff --git a/Source/CBIOS/cbios.asm b/Source/CBIOS/cbios.asm
index 4af347ef..34d8647d 100644
--- a/Source/CBIOS/cbios.asm
+++ b/Source/CBIOS/cbios.asm
@@ -350,33 +350,41 @@ REBOOT:
 ;
 ;__________________________________________________________________________________________________
 WBOOT:
-	LD	SP,STACK	; STACK FOR INITIALIZATION
+;
+#IFDEF PLTWBW
+	; GIVE HBIOS A CHANCE TO DIAGNOSE ISSUES, PRIMARILY
+	; THE OCCURRENCE OF A Z180 INVALID OPCODE TRAP
+	POP	HL			; SAVE PC FOR DIAGNOSIS
+	LD	SP,STACK		; STACK FOR INITIALIZATION
+	LD	BC,$F003		; HBIOS USER RESET FUNCTION
+	RST	08			; DO IT
+#ENDIF
 ;
 #IFDEF PLTUNA
 	; RESTORE COMMAND PROCESSOR FROM UNA BIOS CACHE
-	LD	BC,$01FB	; UNA FUNC = SET BANK
-	LD	DE,(BNKBIOS)	; UBIOS_PAGE (SEE PAGES.INC)
-	RST	08		; DO IT
-	PUSH	DE		; SAVE PREVIOUS BANK
-
-	LD	HL,(CCPBUF)	; ADDRESS OF CCP BUF IN BIOS MEM
-	LD	DE,CCP_LOC	; ADDRESS IN HI MEM OF CCP
-	LD	BC,CCP_SIZ	; SIZE OF CCP
-	LDIR			; DO IT
-
-	LD	BC,$01FB	; UNA FUNC = SET BANK
-	POP	DE		; RECOVER OPERATING BANK
-	RST	08		; DO IT
+	LD	BC,$01FB		; UNA FUNC = SET BANK
+	LD	DE,(BNKBIOS)		; UBIOS_PAGE (SEE PAGES.INC)
+	RST	08			; DO IT
+	PUSH	DE			; SAVE PREVIOUS BANK
+	
+	LD	HL,(CCPBUF)		; ADDRESS OF CCP BUF IN BIOS MEM
+	LD	DE,CCP_LOC		; ADDRESS IN HI MEM OF CCP
+	LD	BC,CCP_SIZ		; SIZE OF CCP
+	LDIR				; DO IT
+	
+	LD	BC,$01FB		; UNA FUNC = SET BANK
+	POP	DE			; RECOVER OPERATING BANK
+	RST	08			; DO IT
 #ELSE
 	; RESTORE COMMAND PROCESSOR FROM CACHE IN HB BANK
-	LD	B,BF_SYSSETCPY	; HBIOS FUNC: SETUP BANK COPY
-	LD	DE,(BNKBIOS)	; D = DEST (USER BANK), E = SRC (BIOS BANK)
-	LD	HL,CCP_SIZ	; HL = COPY LEN = SIZE OF COMMAND PROCESSOR
-	RST	08		; DO IT
-	LD	B,BF_SYSBNKCPY	; HBIOS FUNC: PERFORM BANK COPY
-	LD	HL,(CCPBUF)	; COPY FROM FIXED LOCATION IN HB BANK
-	LD	DE,CCP_LOC	; TO CCP LOCATION IN USR BANK
-	RST	08		; DO IT
+	LD	B,BF_SYSSETCPY		; HBIOS FUNC: SETUP BANK COPY
+	LD	DE,(BNKBIOS)		; D = DEST (USER BANK), E = SRC (BIOS BANK)
+	LD	HL,CCP_SIZ		; HL = COPY LEN = SIZE OF COMMAND PROCESSOR
+	RST	08			; DO IT
+	LD	B,BF_SYSBNKCPY		; HBIOS FUNC: PERFORM BANK COPY
+	LD	HL,(CCPBUF)		; COPY FROM FIXED LOCATION IN HB BANK
+	LD	DE,CCP_LOC		; TO CCP LOCATION IN USR BANK
+	RST	08			; DO IT
 #ENDIF
 ;
 	; SOME APPLICATIONS STEAL THE BDOS SERIAL NUMBER STORAGE
diff --git a/Source/CPM3/bioskrnl.asm b/Source/CPM3/bioskrnl.asm
index bd21c783..85effacf 100644
--- a/Source/CPM3/bioskrnl.asm
+++ b/Source/CPM3/bioskrnl.asm
@@ -172,7 +172,10 @@ boot$1:
 	;	Entry for system restarts.
 
 wboot:
-	lxi sp,boot$stack
+	pop h			; WBW: save PC for diagnosis
+	lxi sp,boot$stack	; reset stack
+	lxi b,0F003H		; WBW: HBIOS user reset func
+	rst 1			; WBW: do it
 	call set$jumps		; initialize page zero
 	call ?rlccp		; reload CCP
 	jmp ccp			; then reset jmp vectors and exit to ccp
diff --git a/Source/HBIOS/Config/RCZ280_nat_zz.asm b/Source/HBIOS/Config/RCZ280_nat_zz.asm
index d9f325c4..e74f9d28 100644
--- a/Source/HBIOS/Config/RCZ280_nat_zz.asm
+++ b/Source/HBIOS/Config/RCZ280_nat_zz.asm
@@ -29,4 +29,4 @@
 RAMLOC		.SET	23		; START OF RAM AS POWER OF 2 (2^N) IN PHYSICAL ADDRESS SPACE
 RAMBIAS		.SET	(1 << (RAMLOC - 10))	; OFFSET OF START OF RAM IN PHYSICAL ADDRESS SPACE
 ;
-Z2U0HFC		.SET	FALSE		; Z2U 0: ENABLE HARDWARE FLOW CONTROL
+Z2U0HFC		.SET	TRUE		; Z2U 0: ENABLE HARDWARE FLOW CONTROL
diff --git a/Source/HBIOS/dbgmon.asm b/Source/HBIOS/dbgmon.asm
index 73691701..5aacfe6c 100644
--- a/Source/HBIOS/dbgmon.asm
+++ b/Source/HBIOS/dbgmon.asm
@@ -120,9 +120,9 @@ SERIALCMDLOOP:
 ;_____________________________________________________________________________
 ;
 INITIALIZE:
-	LD	A,$C3		; JP OPCODE
-	LD	(0),A		; STORE AT $0000
-	LD	(1),HL		; STORE AT $0001
+	;LD	A,$C3		; JP OPCODE
+	;LD	(0),A		; STORE AT $0000
+	;LD	(1),HL		; STORE AT $0001
 
 #IF (BIOS == BIOS_UNA)
 	; INSTALL UNA INVOCATION VECTOR FOR RST 08
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index abbfac72..c5bc7e68 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -201,7 +201,7 @@ RTCDEF		.EQU	0		; ALLOWS DRIVERS TO SET BITS
   #IF (INTMODE == 1)
 	JP	INT_IM1			; JP TO INTERRUPT HANDLER IN HI MEM
   #ELSE
-	RETI				; RETURN W/ INTS DISABLED
+	RET				; RETURN W/ INTS DISABLED
   #ENDIF
 	.FILL	(066H - $),0FFH		; NMI
 	RETN
@@ -2908,6 +2908,8 @@ SYS_RESET:
 	JR	Z,SYS_RESWARM
 	CP	BF_SYSRES_COLD
 	JR	Z,SYS_RESCOLD
+	CP	BF_SYSRES_USER
+	JR	Z,SYS_RESUSER
 	CALL	SYSCHK
 	LD	A,ERR_NOFUNC
 	OR	A			; SIGNAL ERROR
@@ -2916,8 +2918,15 @@ SYS_RESET:
 ; SOFT RESET HBIOS, RELEASE HEAP MEMORY NOT USED BY HBIOS
 ;
 SYS_RESINT:
+;
+	; RESET THE HEAP
 	LD	HL,(HEAPCURB)		; GET HBIOS HEAP THRESHOLD
 	LD	(CB_HEAPTOP),HL		; RESTORE HEAP TOP
+;
+	; MAKE SURE THE PROPER RESET VECTOR IS AT ADDRESS $0000
+	LD	HL,$0040		; USER RESET CODE STUB
+	LD	($0001),HL		; OPERAND OF JP AT $0000
+;
 	XOR	A
 	RET
 ;
@@ -2946,6 +2955,63 @@ SYS_RESCOLD:
 	LD	IX,0			; ADDRESS ZERO
 	CALL	HB_BNKCALL		; DOES NOT RETURN
 ;
+; HOOK CALLED WHEN A USERLAND RESET IS INVOKED, TYPICALLY VIA A JUMP
+; TO LOGICAL CPU ADDRESS $0000
+;
+SYS_RESUSER:
+;
+#IF (CPUFAM == CPU_Z180)
+;
+	IN0	A,(Z180_ITC)		; GET ITC REGISTER
+	BIT	7,A			; TRAP BIT SET?
+	JR	Z,SYS_RESUSER9		; IF NOT, SKIP AHEAD
+;
+	; HANDLE INVALID OPCODE
+	DEC	HL			; BACK UP TO OPCODE START
+	BIT	6,A			; CHECK UFO BIT (2 BYTE OPCODE)
+	JR	Z,SYS_RESUSER1		; IF NOT, ALL SET
+	DEC	HL			; OTHERWISE, BACK UP 1 MORE BYTE
+;
+SYS_RESUSER1:
+	RES	7,A			; CLEAR THE TRAP BIT
+	OUT0	(Z180_ITC),A		; SAVE IT
+;
+	CALL	PRTSTRD			; PRINT ERROR TAG
+	.TEXT	"\r\n\r\n+++ BAD OPCODE @$"
+	CALL	PRTHEXWORDHL		; PRINT ADDRESS
+	PRTS("H:$")			; FORMATTING
+;
+	LD	B,8			; SHOW 8 BYTES
+SYS_RESUSER2:
+	PUSH	BC			; SAVE BC
+	PUSH	HL			; SAVE HL
+	LD	A,(HB_INVBNK)		; GET BYTE FROM INVOKING BANK
+	LD	D,A			; PUT IN D
+	CALL	SYS_PEEK		; PEEK TO GET BYTE VALUE
+	LD	A,E			; PUT IN A
+	CALL	PC_SPACE		; FORMATTING
+	CALL	PRTHEXBYTE		; DISPLAY BYTE
+	POP	HL			; RECOVER HL
+	POP	BC			; RECOVER BC
+	INC	HL			; NEXT BYTE
+	DJNZ	SYS_RESUSER2		; LOOP TIL DONE
+	CALL	NEWLINE			; FORMATTING
+;
+#ENDIF
+;
+SYS_RESUSER9:
+	;; NOTIFY USER
+	;CALL	PRTSTRD
+	;.TEXT	"\r\n*** USER RESET ***\r\n$"
+;
+	;; EXIT VIA USER RESET VECTOR (IF SET)
+	;LD	HL,(HB_RESVEC)		; GET USER RESET VECTOR
+	;LD	A,H			; CHECK IF IT
+	;OR	L			; ... HAS BEEN SET
+	;JP	Z,SYS_RESWARM		; IF NOT, JUST WARM START
+;
+	RET				; ELSE RETURN WITH USER RESET VECTOR IN HL
+;
 ; GET THE CURRENT HBIOS VERSION
 ;   ON INPUT, C=0
 ;   RETURNS VERSION IN DE AS BCD
diff --git a/Source/HBIOS/hbios.inc b/Source/HBIOS/hbios.inc
index bdee24ed..ecb01a9f 100644
--- a/Source/HBIOS/hbios.inc
+++ b/Source/HBIOS/hbios.inc
@@ -90,6 +90,7 @@ BF_SYSINT	.EQU	BF_SYS + 12	; MANAGE INTERRUPT VECTORS
 BF_SYSRES_INT		.EQU	$00	; RESET HBIOS INTERNAL
 BF_SYSRES_WARM		.EQU	$01	; WARM START (RESTART BOOT LOADER)
 BF_SYSRES_COLD		.EQU	$02	; COLD START
+BF_SYSRES_USER		.EQU	$03	; USER RESET REQUEST
 ;
 BF_SYSGET_CIOCNT	.EQU	$00	; GET CHAR UNIT COUNT
 BF_SYSGET_CIOFN		.EQU	$01	; GET CIO UNIT FN/DATA ADR
diff --git a/Source/HBIOS/romldr.asm b/Source/HBIOS/romldr.asm
index 17783fa4..f8f9954b 100644
--- a/Source/HBIOS/romldr.asm
+++ b/Source/HBIOS/romldr.asm
@@ -83,6 +83,20 @@ bid_cur	.equ	-1	; used below to indicate current bank
 #else
 	ret				; return w/ ints disabled
 #endif
+;
+#if (BIOS == BIOS_WBW)
+	.fill	($40 - $),$FF
+	; After initial bootup, it is conventional for a jp 0 to
+	; cause a warm start of the system.  If there is no OS running
+	; then this bit of code will suffice.  After bootup, the
+	; jp instruction at $0 is modified to point here.
+	pop	hl			; save PC in case needed for ...
+	ld	bc,$F003		; HBIOS user reset function
+	call	HB_INVOKE		; do it
+	ld	bc,$F001		; HBIOS warm start function
+	call	HB_INVOKE		; do it
+#endif
+;
 	.fill	($66 - $)
 	retn				; nmi
 ;
@@ -147,6 +161,8 @@ start1:
 	ld	de,0			; put it in user page zero
 	ld	bc,$100			; full page
 	ldir				; do it
+	ld	hl,$0040		; adr of user reset code
+	ld	(1),hl			; save at $0000
 ;
 ; Page zero in user bank is ready for interrupts now.
 ;
diff --git a/Source/Images/Common/TDLBASIC.COM b/Source/Images/Common/TDLBASIC.COM
new file mode 100644
index 00000000..ebaec526
Binary files /dev/null and b/Source/Images/Common/TDLBASIC.COM differ
diff --git a/Source/ver.inc b/Source/ver.inc
index 349e2d90..0874d9c4 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.51"
+#DEFINE BIOSVER	"3.1.1-pre.52"
diff --git a/Source/ver.lib b/Source/ver.lib
index 2ce9dafe..c0a496e9 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.51"
+	db	"3.1.1-pre.52"
 	endm