diff --git a/Source/HBIOS/Config/RPH_std.asm b/Source/HBIOS/Config/RPH_std.asm
index db23d13c..8a3d4b22 100644
--- a/Source/HBIOS/Config/RPH_std.asm
+++ b/Source/HBIOS/Config/RPH_std.asm
@@ -1,6 +1,6 @@
 ;
 ;==================================================================================================
-;   N8 STANDARD CONFIGURATION
+;   RHYOPHYRE STANDARD CONFIGURATION
 ;==================================================================================================
 ;
 ; THE COMPLETE SET OF DEFAULT CONFIGURATION SETTINGS FOR THIS PLATFORM ARE FOUND IN THE
@@ -34,6 +34,8 @@ Z180_CLKDIV	.SET	1		; Z180: CHK DIV: 0=OSC/2, 1=OSC, 2=OSC*2
 Z180_MEMWAIT	.SET	0		; Z180: MEMORY WAIT STATES (0-3)
 Z180_IOWAIT	.SET	1		; Z180: I/O WAIT STATES TO ADD ABOVE 1 W/S BUILT-IN (0-3)
 ;
+RAMSIZE		.SET	512		; SIZE OF RAM IN KB (MUST MATCH YOUR HARDWARE!!!)
+;
 CRTACT		.SET	FALSE		; ACTIVATE CRT (VDU,CVDU,PROPIO,ETC) AT STARTUP
 ;
 PPIDEENABLE	.SET	FALSE		; PPIDE: ENABLE PARALLEL PORT IDE DISK DRIVER (PPIDE.ASM)
diff --git a/Source/HBIOS/asci.asm b/Source/HBIOS/asci.asm
index 537ab3b6..2d118f7b 100644
--- a/Source/HBIOS/asci.asm
+++ b/Source/HBIOS/asci.asm
@@ -621,6 +621,24 @@ ASCI_DETECT:
 ; DUE TO ENCODING BAUD IS ALWAYS DIVISIBLE BY 75
 ; Z180 DIVISOR IS ALWAYS A FACTOR OF 160
 ;
+; CNTLB=	XXPXDSSS
+; FAILSAVE = 	00100000
+;
+; PS (PRESCALE): 0=/10, 1=/30
+; DR (DIVIDE RATIO): 0=/16, 1=/64
+; SS2	SS1	SS0
+; ---	---	---
+; 0	0	0	/1
+; 0	0	1	/2
+; 0	1	0	/4
+; 0	1	1	/8
+; 1	0	0	/16
+; 1	0	1	/32
+; 1	1	0	/64
+;
+; FAILSAFE: CLOCK / 30 / 16 / 1 = CLOCK / 480
+;	IF CLOCK=18432000, BAUD=38400
+;
 ; X := CPU_HZ / 160 / 75 ==> SIMPLIFIED ==> X := CPU_KHZ / 12
 ; X := X / (BAUD / 75)
 ; IF X % 3 == 0, THEN (PS := 1, X := X / 3) ELSE PS=0
diff --git a/Source/HBIOS/dsrtc.asm b/Source/HBIOS/dsrtc.asm
index 932481c1..9b8c630d 100644
--- a/Source/HBIOS/dsrtc.asm
+++ b/Source/HBIOS/dsrtc.asm
@@ -66,16 +66,16 @@
 ; RTC LATCH WRITE
 ; ---------------
 ;
-; BIT	SBC	SBC-004	MFPIC	N8	N8-CSIO	MK4	SC130	SC131	SC126		MBC	RPH	
-; -----	-------	-------	-------	-------	-------	-------	-------	-------	---------------	------- -------	
-; D7	RTC_OUT RTC_OUT	--	RTC_OUT RTC_OUT	RTC_OUT	--	--	RTC_OUT,I2C_SDA	RTC_OUT RTC_OUT 
-; D6	RTC_CLK RTC_CLK	--	RTC_CLK RTC_CLK	RTC_CLK	--	--	RTC_CLK		RTC_CLK RTC_CLK 
-; D5	/RTC_WE /RTC_WE	--	/RTC_WE /RTC_WE	/RTC_WE	--	--	/RTC_WE		/RTC_WE /RTC_WE 
-; D4	RTC_CE	RTC_CE	--	RTC_CE  RTC_CE	RTC_CE	--	--	RTC_CE		RTC_CE  RTC_CE	
-; D3	NC	CLKSEL	/RTC_CE	NC	NC	NC	--	--	/SPI_CS2	CLKSEL  NC	
-; D2	NC	SPK	RTC_CLK	SPI_CS	SPI_CS	NC	/SPI_CS1/SPI_CS1/SPI_CS1	SPK     NC	
-; D1	--	--	RTC_WE	SPI_CLK	NC	NC	--	--	FS		LED1    NC	
-; D0	--	--	RTC_OUT	SPI_DI	NC	NC	--	--	I2C_SCL		LED0    NC	
+; BIT	SBC	SBC-004	MFPIC	N8	N8-CSIO	MK4	SC130	SC131	SC126		MBC	RPH
+; -----	-------	-------	-------	-------	-------	-------	-------	-------	---------------	------- -------
+; D7	RTC_OUT RTC_OUT	--	RTC_OUT RTC_OUT	RTC_OUT	--	--	RTC_OUT,I2C_SDA	RTC_OUT	RTC_OUT
+; D6	RTC_CLK RTC_CLK	--	RTC_CLK RTC_CLK	RTC_CLK	--	--	RTC_CLK		RTC_CLK	RTC_CLK
+; D5	/RTC_WE /RTC_WE	--	/RTC_WE /RTC_WE	/RTC_WE	--	--	/RTC_WE		/RTC_WE	/RTC_WE
+; D4	RTC_CE	RTC_CE	--	RTC_CE  RTC_CE	RTC_CE	--	--	RTC_CE		RTC_CE	RTC_CE
+; D3	NC	CLKSEL	/RTC_CE	NC	NC	NC	--	--	/SPI_CS2	CLKSEL	--
+; D2	NC	SPK	RTC_CLK	SPI_CS	SPI_CS	NC	/SPI_CS1/SPI_CS1/SPI_CS1	SPK	--
+; D1	--	--	RTC_WE	SPI_CLK	NC	NC	--	--	FS		LED1	--
+; D0	--	--	RTC_OUT	SPI_DI	NC	NC	--	--	I2C_SCL		LED0	--
 ;
 ; RTC LATCH READ
 ; --------------
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 40900c2a..b2e8ed35 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -1946,20 +1946,20 @@ HB_CPUSPD2:
 ;
 	LD	HL,(HB_CPUOSC)	; INIT HL TO CPU OSC FREQ (KHZ)
 ;
-  #IF (Z180_CLKDIV == 0)
 	; ADJUST HL TO REFLECT HALF SPEED OPERATION
 	SRL	H		; ADJUST HL ASSUMING
 	RR	L		; HALF SPEED OPERATION
-  #ENDIF
 ;	
-  #IF (Z180_CLKDIV == 1)
+  #IF (Z180_CLKDIV >= 1)
 	LD	A,(HB_CPUTYPE)	; GET CPU TYPE
 	CP	2		; Z8S180 REV K OR BETTER?
 	JR	C,HB_CPU3	; IF NOT, NOT POSSIBLE!
 	; SET CLOCK DIVIDE TO 1 RESULTING IN FULL XTAL SPEED
 	LD	A,$80
 	OUT0	(Z180_CCR),A
-	; HL ALREADY REFLECTS FULL SPEED OPERATION
+	; ADJUST HL TO REFLECT FULL SPEED OPERATION
+	SLA	L
+	RL	H
   #ENDIF
 ;
   #IF (Z180_CLKDIV >= 2)
@@ -4102,19 +4102,33 @@ SYS_GETCPUSPD1:
 #ENDIF
 ;
 #IF (CPUFAM == CPU_Z180)
-	IN0	A,(Z180_CMR)		; GET CLOCK MULTIPLIER
-	RLCA				; ROTATE BIT TO BIT 0
-	AND	%00000001		; ISOLATE IT
-	LD	H,A			; SAVE IN H
+	LD	HL,0			; INIT CPU SPEED TO HALF
+	LD	A,(HB_CPUTYPE)		; LOAD CPUTYPE
+	CP	2			; S-CLASS OR ABOVE?
+	JR	C,SYS_GETCPUSPD1	; IF NOT, NO CCR/CMR
+;
+	; GET CCR BIT
 	IN0	A,(Z180_CCR)		; GET CLOCK CONTROL
 	RLCA				; ROTATE BIT TO BIT 0
 	AND	%00000001		; ISOLATE IT
 	LD	L,A			; SAVE IN L
+;
+	LD	A,(HB_CPUTYPE)		; LOAD CPUTYPE
+	CP	3			; REV. N?
+	JR	C,SYS_GETCPUSPD1	; IF NOT, NO CMR
+;
+	; GET CMR BIT
+	IN0	A,(Z180_CMR)		; GET CLOCK MULTIPLIER
+	RLCA				; ROTATE BIT TO BIT 0
+	AND	%00000001		; ISOLATE IT
+	LD	H,A			; SAVE IN H
+;
+SYS_GETCPUSPD1:
+	; CALC FINAL MULTIPLIER TO L
 	XOR	A			; CLEAR ACCUM
 	ADD	A,H			; ADD IN CMR BIT
 	ADD	A,L			; ADD IN CCR BIT
 	LD	L,A			; SAVE RESULT IN L
-;
 	; DCNTL = MMII????
 	IN0	A,(Z180_DCNTL)		; GET WAIT STATES
 	RLCA				; ROTATE MEM WS BITS
@@ -4378,6 +4392,29 @@ SYS_SETCPUSPD3:
 #ENDIF
 ;
 #IF (CPUFAM == CPU_Z180)
+	; VERIFY THAT REQUESTED SETTINGS ARE ALLOWED BY HARDWARE
+	LD	A,L			; GET SPEED REQUESTED
+	CP	$FF			; NO CHANGE?
+	JR	Z,SYS_SETCPUSPD0A	; SKIP CHECK
+	LD	A,(HB_CPUTYPE)		; 1=ORIG, 2=REVK, 3=REVN
+	INC	L			; 1=HALF,2=FULL,3=DOUBLE
+	CP	L			; TOO HIGH FOR CPU TYPE?
+	JP	C,SYS_SETCPUSPD_ERR	; CPU CAN'T DO SPD MULT
+	DEC	L			; RESTORE ORIG REQUEST
+SYS_SETCPUSPD0A:
+	LD	A,D			; MEM WS
+	CP	$FF			; NO CHANGE?
+	JR	Z,SYS_SETCPUSPD0B	; SKIP CHECK
+	CP	4			; TOO HIGH?
+	JP	NC,SYS_SETCPUSPD_ERR	; >3 IS TOO HIGH
+SYS_SETCPUSPD0B:
+	LD	A,D			; I/O WS
+	CP	$FF			; NO CHANGE?
+	JR	Z,SYS_SETCPUSPD0C	; SKIP CHECK
+	CP	4			; TOO HIGH?
+	JP	NC,SYS_SETCPUSPD_ERR	; >3 IS TOO HIGH
+SYS_SETCPUSPD0C:
+;
 	PUSH	DE			; SAVE WAIT STATES FOR NOW
 	; BEFORE IMPLEMENTING THE NEW CPU SPEED, WE SWITCH THE
 	; WAIT STATES TO MAXIMUM BECAUSE WE MAY BE IMPLEMENTING
@@ -4404,11 +4441,11 @@ SYS_SETCPUSPD1:
 	LD	C,%10000000		; SET CCR BIT
 SYS_SETCPUSPD2:
 ;
+	; IMPLEMENT THE NEW CPU SPEED
 	IN0	A,(Z180_CMR)
 	AND	~%10000000
 	OR	B
 	OUT0	(Z180_CMR),A
-;
 	IN0	A,(Z180_CCR)
 	AND	~%10000000
 	OR	C
diff --git a/Source/ver.inc b/Source/ver.inc
index 30a350fb..a7451543 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.167"
+#DEFINE BIOSVER	"3.1.1-pre.168"
diff --git a/Source/ver.lib b/Source/ver.lib
index 846b8a49..dc0185e8 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.167"
+	db	"3.1.1-pre.168"
 	endm