diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 602ba097..f9286cca 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -1957,7 +1957,8 @@ ROMRESUME:
 #ENDIF
 ;
 #IF (MEMMGR == MM_MSX)
-	LD	A,((ROMSIZE + RAMSIZE) / 16) - 2 + RAMBIAS * 2
+RAMSEG	.EQU	((ROMSIZE + RAMSIZE) / 16) - 2 + (RAMBIAS * 2)
+	LD	A,RAMSEG
 	OUT	(MPGSEL_2),A
 	INC	A
 	OUT	(MPGSEL_3),A
diff --git a/Source/HBIOS/rp5rtc.asm b/Source/HBIOS/rp5rtc.asm
index b86ddf70..98a93112 100644
--- a/Source/HBIOS/rp5rtc.asm
+++ b/Source/HBIOS/rp5rtc.asm
@@ -324,6 +324,9 @@ RP5RTC_SETTIM:
 
 	LD	B, REG_1YEAR
 	LD	A, (RP5RTC_YR)
+	; 2-DIGIT YEAR IS RELATIVE TO BASE YEAR 1980
+	ADD	A,$20			; ADD OFFSET
+	DAA				; BCD
 	CALL	RP5RTC_WRVL
 
 	LD	B, MODE_ALRMST
@@ -378,6 +381,9 @@ RP5RTC_RDTIM:
 
 	LD	B, REG_1YEAR
 	CALL	RP5RTC_RDVL
+	; 2-DIGIT YEAR IS RELATIVE TO BASE YEAR 1980
+	SUB	$20			; SUBSTRACT OFFSET
+	DAA				; BCD
 	LD	(RP5RTC_YR), A
 
 	RET