diff --git a/Doc/ROM Applications.pdf b/Doc/ROM Applications.pdf
index 5d7c2dac..26d4f1a6 100644
Binary files a/Doc/ROM Applications.pdf and b/Doc/ROM Applications.pdf differ
diff --git a/Doc/RomWBW Applications.pdf b/Doc/RomWBW Applications.pdf
index bb6a0000..9810891d 100644
Binary files a/Doc/RomWBW Applications.pdf and b/Doc/RomWBW Applications.pdf differ
diff --git a/Doc/RomWBW Architecture.pdf b/Doc/RomWBW Architecture.pdf
index 8a8dd61e..34cf545a 100644
Binary files a/Doc/RomWBW Architecture.pdf and b/Doc/RomWBW Architecture.pdf differ
diff --git a/Doc/RomWBW Disk Catalog.pdf b/Doc/RomWBW Disk Catalog.pdf
index c5255721..2ae54ac0 100644
Binary files a/Doc/RomWBW Disk Catalog.pdf and b/Doc/RomWBW Disk Catalog.pdf differ
diff --git a/Doc/RomWBW Getting Started.pdf b/Doc/RomWBW Getting Started.pdf
index 6f4a2b3c..0158aa4a 100644
Binary files a/Doc/RomWBW Getting Started.pdf and b/Doc/RomWBW Getting Started.pdf differ
diff --git a/ReadMe.md b/ReadMe.md
index 7d626167..b8fa89eb 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -3,7 +3,7 @@ author: "Wayne Warthen (mailto:wwarthen@gmail.com)"
 classoption:
 - oneside
 colorlinks: true
-date: 01 Feb 2022
+date: 02 Feb 2022
 documentclass: book
 fontfamily: helvet
 fontsize: 12pt
@@ -44,7 +44,7 @@ toc-depth: 1
 ## Z80/Z180 System Software
 
 Version 3.1 Pre-release  
-01 Feb 2022
+02 Feb 2022
 
 Wayne Warthen <wwarthen@gmail.com>
 
@@ -455,7 +455,7 @@ therefore, globally available.
 | TALK        | Direct console I/O to a specified character device.                                                  |
 | RTC         | Manage and test the Real Time Clock hardware.                                                        |
 | TIMER       | Display value of running periodic system timer.                                                      |
-| INTTEST     | Test interrupt vector hooking.                                                                       |
+| CPUSPD      | Change the running CPU speed and wait states of the system.                                          |
 
 Some custom applications do not fit on the ROM disk. They are found on
 the disk image files or the individual files can be found in the
@@ -465,6 +465,7 @@ Binary\\Apps directory of the distribution.
 |-------------|-------------------------------------------------------------|
 | TUNE        | Play .PT2, .PT3, .MYM audio files.                          |
 | FAT         | Access MS-DOS FAT filesystems from RomWBW (based on FatFs). |
+| INTTEST     | Test interrupt vector hooking.                              |
 
 Additional documentation on all of these applications can be found in
 “RomWBW Applications.pdf” in the Doc directory of the distribution.
diff --git a/ReadMe.txt b/ReadMe.txt
index b94fb4d5..92cfdabb 100644
--- a/ReadMe.txt
+++ b/ReadMe.txt
@@ -1,6 +1,6 @@
 RomWBW Getting Started
 Wayne Warthen (mailto:wwarthen@gmail.com)
-01 Feb 2022
+02 Feb 2022
 
 
 
@@ -17,7 +17,7 @@ RomWBW
 Z80/Z180 System Software
 
 Version 3.1 Pre-release
-01 Feb 2022
+02 Feb 2022
 
 Wayne Warthen wwarthen@gmail.com
 
@@ -460,7 +460,7 @@ therefore, globally available.
 
   TIMER         Display value of running periodic system timer.
 
-  INTTEST       Test interrupt vector hooking.
+  CPUSPD        Change the running CPU speed and wait states of the system.
   -----------------------------------------------------------------------------
 
 Some custom applications do not fit on the ROM disk. They are found on
@@ -471,6 +471,7 @@ Binary\Apps directory of the distribution.
   ------------- -------------------------------------------------------------
   TUNE          Play .PT2, .PT3, .MYM audio files.
   FAT           Access MS-DOS FAT filesystems from RomWBW (based on FatFs).
+  INTTEST       Test interrupt vector hooking.
 
 Additional documentation on all of these applications can be found in
 “RomWBW Applications.pdf” in the Doc directory of the distribution.
diff --git a/Source/Apps/cpuspd/cpuspd.asm b/Source/Apps/cpuspd/cpuspd.asm
index 0aecb7f8..363c4e75 100644
--- a/Source/Apps/cpuspd/cpuspd.asm
+++ b/Source/Apps/cpuspd/cpuspd.asm
@@ -21,6 +21,11 @@ rtc_port	.equ	$70		; RTC latch port adr
 restart		.equ	$0000		; CP/M restart vector
 bdos		.equ	$0005		; BDOS invocation vector
 ;
+ident		.equ	$FFFE		; loc of RomWBW HBIOS ident ptr
+;
+rmj		.equ	3		; intended CBIOS version - major
+rmn		.equ	1		; intended CBIOS version - minor
+;
 ;=======================================================================
 ;
 	.org	$100	; standard CP/M executable
@@ -33,6 +38,10 @@ bdos		.equ	$0005		; BDOS invocation vector
 	call	crlf
 	ld	de,str_banner		; banner
 	call	prtstr
+;
+	; initialization
+	call	init			; initialize
+	jr	nz,exit			; abort if init fails
 ;
 	call	main			; do the real work
 ;
@@ -47,6 +56,46 @@ exit:
 ; Main Program
 ;=======================================================================
 ;
+;
+; Initialization
+;
+init:
+	; check for UNA (UBIOS)
+	ld	a,($FFFD)	; fixed location of UNA API vector
+	cp	$C3		; jp instruction?
+	jr	nz,initwbw	; if not, not UNA
+	ld	hl,($FFFE)	; get jp address
+	ld	a,(hl)		; get byte at target address
+	cp	$FD		; first byte of UNA push ix instruction
+	jr	nz,initwbw	; if not, not UNA
+	inc	hl		; point to next byte
+	ld	a,(hl)		; get next byte
+	cp	$E5		; second byte of UNA push ix instruction
+	jr	nz,initwbw	; if not, not UNA
+	jp	err_una		; UNA not supported
+;
+initwbw:
+	; get location of config data and verify integrity
+	ld	hl,(ident)	; HL := adr or RomWBW HBIOS ident
+	ld	a,(hl)		; get first byte of RomWBW marker
+	cp	'W'		; match?
+	jp	nz,err_inv	; abort with invalid config block
+	inc	hl		; next byte (marker byte 2)
+	ld	a,(hl)		; load it
+	cp	~'W'		; match?
+	jp	nz,err_inv	; abort with invalid config block
+	inc	hl		; next byte (major/minor version)
+	ld	a,(hl)		; load it
+	cp	rmj << 4 | rmn	; match?
+	jp	nz,err_ver	; abort with invalid os version
+;
+initz:
+	; initialization complete
+	xor	a		; signal success
+	ret			; return
+;
+;
+;
 main:
 	; skip to start of first parm
 	ld	ix,$81		; point to start of parm area (past len byte)
@@ -64,13 +113,19 @@ main1:
 	jr	main1		; continue option checking
 ;
 main2:
+	ret	z		; if end, nothing to do
+	cp	','		; no new speed?
+	jr	z,main2a	; go to wait states
 	; parse speed string (half, full, double)
 	call	getalpha	; extract speed ("HALF", "FULL", "DOUBLE")
-;
+	call	parse_spd	; parse to numeric
+	jp	c,err_parm	; if invalid, abort
+	ld	(new_cpu_spd),a	; save it
 	call	nonblank	; skip whitespace
 	jp	z,set_spd	; if nothing else, set new speed
 	cp	','		; parm separator
 	jp	nz,err_parm	; invalid format, show usage and abort
+main2a:
 	inc	ix		; pass separator
 	call	nonblank	; skip whitespace
 	jp	z,set_spd	; if nothing else, set new speed
@@ -78,7 +133,7 @@ main2:
 	jr	c,main3		; nope, try skipping this parm
 	call	getnum		; get memory wait states
 	jp	c,err_parm	; if overflow, show usage and abort
-	ld	(ws_mem),a	; save memory wait states
+	ld	(new_ws_mem),a	; save memory wait states
 ;
 main3:
 	call	nonblank	; skip whitespace
@@ -90,42 +145,40 @@ main3:
 	jp	z,set_spd	; if nothing else, set new speed
 	call	getnum		; get I/O wait states
 	jp	c,err_parm	; if overflow, show usage and abort
-	ld	(ws_io),a	; save memory wait states
+	ld	(new_ws_io),a	; save memory wait states
 ;
 	call	nonblank	; skip whitespace
 	jp	nz,err_parm	; invalid format, show usage and abort
-	;
-;
-set_spd:
-	ld	a,(tmpstr)
-	cp	'H'
-	jr	z,set_half
-	cp	'F'
-	jr	z,set_full
-	cp	'D'
-	jr	z,set_dbl
-	jp	err_parm
+	jp	set_spd		; set new speed and return
+;
+parse_spd:
+	ld	a,(tmpstr)		; first byte of string
+	ld	c,0			; assume half speed
+	cp	'H'			; check it
+	jr	z,parse_spd1		; if equal, done
+	ld	c,1			; assume full speed
+	cp	'F'			; check it
+	jr	z,parse_spd1		; if equal, done
+	ld	c,2			; assume double speed
+	cp	'D'			; check it
+	jr	z,parse_spd1		; if equal, done
+	or	a			; clear CF
+	ccf				; set CF to indicate error
+	ret
+parse_spd1:
+	ld	a,c			; result to a
+	or	a			; clear CF
 	ret
 ;
-set_half:
-	ld	l,0
-	jr	new_spd
-;
-set_full:
-	ld	l,1
-	jr	new_spd
-;
-set_dbl:
-	ld	l,2
-	jr	new_spd
-;
-new_spd:
+set_spd:
 	call	delay
 	ld	b,BF_SYSSET
 	ld	c,BF_SYSSET_CPUSPD
-	ld	a,(ws_mem)
+	ld	a,(new_cpu_spd)
+	ld	l,a
+	ld	a,(new_ws_mem)
 	ld	d,a
-	ld	a,(ws_io)
+	ld	a,(new_ws_io)
 	ld	e,a
 	rst	08
 	jp	nz,err_not_sup
@@ -134,6 +187,19 @@ new_spd:
 	ret
 ;
 show_spd:
+	ld	b,BF_SYSGET
+	ld	c,BF_SYSGET_CPUINFO
+	rst	08
+	jp	nz,err_not_sup
+	call	crlf2
+	push	de			; save CPU speed for now
+	push	bc			; Oscillator speed to HL
+	pop	hl
+	ld	de,str_spacer
+	call	prtstr
+	call	prtd3m			; print it
+	ld	de,str_oscspd
+	call	prtstr
 	ld	b,BF_SYSGET
 	ld	c,BF_SYSGET_CPUSPD
 	rst	08
@@ -151,10 +217,15 @@ show_spd:
 	jr	z,show_spd1
 	jp	err_invalid
 show_spd1:
-	call	crlf2
+	call	crlf
+	call	prtstr
+	pop	bc			; recover wait states
+	pop	hl			; recover CPU speed
+	push	bc			; resave wait states
+	call	prtd3m
+	ld	de,str_cpuspd
 	call	prtstr
 	pop	hl
-;
 	ld	a,h			; memory wait states
 	cp	$FF
 	jr	z,show_spd2
@@ -198,6 +269,15 @@ usage:
 ;
 ; Error Handlers
 ;
+err_una:
+	ld	de,str_err_una
+	jr	err_ret
+err_inv:
+	ld	de,str_err_inv
+	jr	err_ret
+err_ver:
+	ld	de,str_err_ver
+	jr	err_ret
 err_parm:
 	ld	de,str_err_parm
 	jr	err_ret
@@ -235,8 +315,9 @@ prtchr:
 	pop	af
 	ret
 ;
-prtdot:
+; Print a dot character without destroying any registers
 ;
+prtdot:
 	; shortcut to print a dot preserving all regs
 	push	af		; save af
 	ld	a,'.'		; load dot char
@@ -389,6 +470,46 @@ prtdec2:
 	ld	e,0
 	call	prtchr
 	ret
+;
+; Print value of HL as thousandths, ie. 0.000
+;
+prtd3m:
+	push	bc
+	push	de
+	push	hl
+	ld	e,'0'
+	ld	bc,-10000
+	call	prtd3m1
+	ld	e,0
+	ld	bc,-1000
+	call	prtd3m1
+	call	prtdot
+	ld	bc,-100
+	call	prtd3m1
+	ld	c,-10
+	call	prtd3m1
+	ld	c,-1
+	call	prtd3m1
+	pop	hl
+	pop	de
+	pop	bc
+	ret
+prtd3m1:
+	ld	a,'0' - 1
+prtd3m2:
+	inc	a
+	add	hl,bc
+	jr	c,prtd3m2
+	sbc	hl,bc
+	cp	e
+	jr	z,prtd3m3
+	ld	e,0
+	call	prtchr
+prtd3m3:
+	ret
+
+
+
 ;
 ; Get the next non-blank character from (HL).
 ;
@@ -541,17 +662,29 @@ delay1:
 ; Constants
 ;=======================================================================
 ;
-str_banner		.db	"RomWBW CPU Speed Selector v0.4, 31-Jan-2022",0
+str_banner		.db	"RomWBW CPU Speed Selector v0.5, 2-Feb-2022",0
 str_spacer		.db	"  ",0
-str_slow		.db	"  CPU speed is HALF",0
-str_full		.db	"  CPU speed is FULL",0
-str_dbl			.db	"  CPU speed is DOUBLE",0
+str_oscspd		.db	" MHz Oscillator",0
+str_slow		.db	"  CPU speed is HALF (",0
+str_full		.db	"  CPU speed is FULL (",0
+str_dbl			.db	"  CPU speed is DOUBLE (",0
+str_cpuspd		.db	" MHz)",0
 str_memws		.db	" Memory Wait State(s)",0
 str_iows		.db	" I/O Wait State(s)",0
-str_err_parm		.db	"  Parameter error (CPUSPD /? for usage)",0
+str_err_una		.db	"  ERROR: UNA not supported by application",0
+str_err_inv		.db	"  ERROR: Invalid BIOS (signature missing)",0
+str_err_ver		.db	"  ERROR: Unexpected HBIOS version",0
+str_err_parm		.db	"  ERROR: Parameter error (CPUSPD /? for usage)",0
 str_err_not_sup		.db	"  ERROR: Platform or configuration not supported!",0
 str_err_invalid		.db	"  ERROR: Invalid configuration!",0
-str_usage		.db	"  Usage: CPUSPD [(Half|Full|Double)[,<Memory Waits>[,<I/O Waits>]]]",0
+str_usage		.db	"  Usage: CPUSPD <cpuspd>,<memws>,<iows>\r\n"
+			.db	"\r\n"
+			.db	"         <cpuspd>: \"Half\", \"Full\", or \"Double\"\r\n"
+			.db	"         <memws>:  Memory wait states\r\n"
+			.db	"         <iows>:   I/O wait states\r\n"
+			.db	"\r\n"
+			.db	"         Any parameter may be omitted\r\n"
+			.db	"         Ability to set values varies by system\r\n",0
 ;
 ;=======================================================================
 ; Working data
@@ -563,8 +696,9 @@ stack		.equ	$		; stack top
 ;
 ;
 tmpstr		.fill	9,0		; temp string (8 chars, 0 term)
-ws_mem		.db	$FF		; memory wait states
-ws_io		.db	$FF		; I/O wait states
+new_cpu_spd	.db	$FF		; new CPU speed
+new_ws_mem	.db	$FF		; new memory wait states
+new_ws_io	.db	$FF		; new I/O wait states
 
 
 ;
diff --git a/Source/Doc/Architecture.md b/Source/Doc/Architecture.md
index 6d542843..cff5522d 100644
--- a/Source/Doc/Architecture.md
+++ b/Source/Doc/Architecture.md
@@ -1938,6 +1938,7 @@ lookup.
 |           H: Z80 CPU Variant
 |           L: CPU Speed in MHz
 |           DE: CPU Speed in KHz
+|           BC: Oscillator Speed in KHz
 
 #### SYSGET Subfunction 0xF1 -- Get Memory Information (MEMINFO)
 
diff --git a/Source/HBIOS/API.txt b/Source/HBIOS/API.txt
index aeae56e9..af68ecfe 100644
--- a/Source/HBIOS/API.txt
+++ b/Source/HBIOS/API.txt
@@ -100,6 +100,7 @@ GET ($F8):
                                                 H=Z80 CPU Variant
                                                 L=CPU Speed in MHz
                                                 DE=CPU Speed in KHz
+						BC=Oscillator Freq in KHz
 
     MEMINFO ($F1):
       BC=FuSnction/Subfunction                   A=Result
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 5e6cfe42..f8146f48 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -3832,6 +3832,7 @@ SYS_GETCPUINFO:
 	LD	A,(CB_CPUMHZ)
 	LD	L,A
 	LD	DE,(CB_CPUKHZ)
+	LD	BC,(HB_CPUOSC)
 	XOR	A
 	RET
 ;
@@ -4106,6 +4107,8 @@ SYS_SETCPUSPD:
 ; NOTE: WAIT STATE SETTINGS ARE IGNORED FOR Z80
 ;
 	LD	A,L			; CLK SPD TO ACCUM
+	CP	$FF			; NO CHANGE?
+	JR	Z,SYS_SETCPUSPD3	; DONE IF SO
 	LD	C,%00000000		; HALF SPEED
 	CP	0
 	JR	Z,SYS_SETCPUSPD1
@@ -4154,13 +4157,27 @@ SYS_SETCPUSPD2:
 	LD	A,(CB_CPUMHZ)		; CPU SPEED TO ACCUM AND INIT
 	CALL	DELAY_INIT		; .. SPEED COMPENSATED DELAY
 ;
+SYS_SETCPUSPD3:
 	XOR	A
 	RET
 #ENDIF
 ;
 #IF (CPUFAM == CPU_Z180)
 	PUSH	DE			; SAVE WAIT STATES FOR NOW
-	LD	A,L			; CLK SPD TO ACCUM
+	; BEFORE IMPLEMENTING THE NEW CPU SPEED, WE SWITCH THE
+	; WAIT STATES TO MAXIMUM BECAUSE WE MAY BE IMPLEMENTING
+	; SLOWER WAIT STATES REQUIRED BY THE NEW SPEED.  WE SAVE
+	; THE ORIGINAL WAIT STATES REGISTER VALUE ON STACK
+	IN0	A,(Z180_DCNTL)		; GET CURRENT REGISTER VALUE
+	LD	E,A			; PUT IN E
+	PUSH	DE			; SAVE FOR LATER
+	OR	%11110000		; MAX WAIT STATES
+	OUT0	(Z180_DCNTL),A		; DO IT
+;
+	LD	A,L			; NEW CLK SPD TO ACCUM
+	CP	$FF			; NO CHANGE?
+	JR	Z,SYS_SETCPUSPD2B	; IF SO, SKIP TO WAIT STATES
+;
 	LD	B,0			; B HAS BIT FOR CMR
 	LD	C,0			; C HAS BIT FOR CCR
 	CP	2			; DOUBLE SPEED?
@@ -4171,15 +4188,6 @@ SYS_SETCPUSPD1:
 	JR	C,SYS_SETCPUSPD2	; <1?, SKIP AHEAD
 	LD	C,%10000000		; SET CCR BIT
 SYS_SETCPUSPD2:
-	; BEFORE IMPLEMENTING THE NEW CPU SPEED, WE SWITCH THE
-	; WAIT STATES TO MAXIMUM BECAUSE WE MAY BE IMPLEMENTING
-	; SLOWER WAIT STATES REQUIRED BY THE NEW SPEED.  WE SAVE
-	; THE ORIGINAL WAIT STATES REGISTER VALUE ON STACK
-	IN0	A,(Z180_DCNTL)		; GET CURRENT REGISTER VALUE
-	LD	E,A			; PUT IN L
-	PUSH	DE			; SAVE FOR LATER
-	OR	%11110000		; MAX WAIT STATES
-	OUT0	(Z180_DCNTL),A		; DO IT
 ;
 	IN0	A,(Z180_CMR)
 	AND	~%10000000
@@ -4223,8 +4231,9 @@ SETCPUSPD2A:
 	ADC	A,C			; C -> A; ADD CF FOR ROUNDING
 	LD	(CB_CPUMHZ),A		; SAVE IT
 ;
+SYS_SETCPUSPD2B:
 	; NOW IMPLEMENT ANY WAIT STATE CHANGES.
-	POP	HL			; INIT L WITH ORIG VALUE
+	POP	HL			; INIT L WITH ORIG DCNTL VALUE
 	POP	DE			; RECOVER WAIT STATES
 	LD	A,D			; GET MEM WS
 	CP	$FF			; SKIP?
diff --git a/Source/ver.inc b/Source/ver.inc
index c670d283..0ed9e30c 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.152"
+#DEFINE BIOSVER	"3.1.1-pre.153"
diff --git a/Source/ver.lib b/Source/ver.lib
index 4c6b0ca3..06000c8a 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.152"
+	db	"3.1.1-pre.153"
 	endm