diff --git a/Source/HBIOS/ds7rtc.asm b/Source/HBIOS/ds7rtc.asm
index 262ca0af..ed33e638 100644
--- a/Source/HBIOS/ds7rtc.asm
+++ b/Source/HBIOS/ds7rtc.asm
@@ -101,8 +101,7 @@ DS7_DISPATCH:
 	DEC	A
 	JP	Z, DS7_DEVICE			; REPORT RTC DEVICE INFO
 	CALL	SYSCHK
-	LD	A,ERR_NOFUNC
-	OR	A
+	SYSCHKERR(ERR_NOFUNC)
 	RET
 ;
 ;-----------------------------------------------------------------------------
@@ -269,9 +268,7 @@ DS7_GETBLK:
 DS7_SETBLK:
 DS7_SETALM
 DS7_GETALM
-	CALL	SYSCHK
-	LD	A,ERR_NOTIMPL
-	OR	A
+	SYSCHKERR(ERR_NOTIMPL)
 	RET
 ;-----------------------------------------------------------------------------
 ; REPORT RTC DEVICE INFO
diff --git a/Source/HBIOS/hdsk.asm b/Source/HBIOS/hdsk.asm
index 3526e330..172595a6 100644
--- a/Source/HBIOS/hdsk.asm
+++ b/Source/HBIOS/hdsk.asm
@@ -121,9 +121,7 @@ HDSK_FNTBL:
 HDSK_VERIFY:
 HDSK_FORMAT:
 HDSK_DEFMED:
-	CALL	SYSCHK			; INVALID SUB-FUNCTION
-	LD	A,ERR_NOTIMPL
-	OR	A
+	SYSCHKERR(ERR_NOTIMPL)			; INVALID SUB-FUNCTION
 	RET
 ;
 ;
diff --git a/Source/HBIOS/intrtc.asm b/Source/HBIOS/intrtc.asm
index 6602b3a3..cbb2184f 100644
--- a/Source/HBIOS/intrtc.asm
+++ b/Source/HBIOS/intrtc.asm
@@ -56,9 +56,7 @@ INTRTC_DISPATCH:
 	JP	Z,INTRTC_SETALM	; SET ALARM 
 	DEC	A
 	JP	Z,INTRTC_DEVICE	; REPORT RTC DEVICE INFO
-	CALL	SYSCHK
-	LD	A,ERR_NOFUNC
-	OR	A
+	SYSCHKERR(ERR_NOFUNC)
 	RET
 ;
 ; NVRAM FUNCTIONS ARE NOT AVAILABLE IN SIMULATOR
@@ -69,9 +67,7 @@ INTRTC_GETBLK:
 INTRTC_SETBLK:
 INTRTC_GETALM:
 INTRTC_SETALM:
-	CALL	SYSCHK
-	LD	A,ERR_NOTIMPL
-	OR	A
+	SYSCHKERR(ERR_NOTIMPL)
 	RET
 ;
 ; RTC GET TIME
@@ -205,7 +201,7 @@ INTRTC_INT2:
 	JR	NZ,INTRTC_INTX		; NOPE, DONE
 	LD	(HL),0			; BACK TO YEAR ZERO
 INTRTC_INTX:
-	JP	SYSCHK
+	JP	PANIC
 INTRTC_VEC	.EQU	$-2
 ;
 ; CONVERT FROM BINARY BUF (HL) TO BCD BUF (DE)
diff --git a/Source/HBIOS/rp5rtc.asm b/Source/HBIOS/rp5rtc.asm
index 4fe0a677..df74a42d 100644
--- a/Source/HBIOS/rp5rtc.asm
+++ b/Source/HBIOS/rp5rtc.asm
@@ -159,9 +159,7 @@ RP5RTC_DISPATCH:
 	JP	Z,RP5RTC_SETALM		; SET ALARM
 	DEC	A
 	JP	Z,RP5RTC_DEVICE		; REPORT RTC DEVICE INFO
-	CALL	SYSCHK
-	LD	A, ERR_NOFUNC
-	OR	A
+	SYSCHKERR(ERR_NOFUNC)
 	RET
 ;
 ; RTC GET NVRAM BYTE
@@ -240,9 +238,7 @@ RP5RTC_GETBLK:
 RP5RTC_SETBLK:
 RP5RTC_GETALM:
 RP5RTC_SETALM:
-	LD	A, ERR_NOTIMPL
-	CALL	SYSCHK
-	OR	A
+	SYSCHKERR(ERR_NOTIMPL)
 	RET
 ;
 ; RTC GET TIME
diff --git a/Source/HBIOS/simrtc.asm b/Source/HBIOS/simrtc.asm
index f144d1aa..3a562f18 100644
--- a/Source/HBIOS/simrtc.asm
+++ b/Source/HBIOS/simrtc.asm
@@ -55,9 +55,7 @@ SIMRTC_DISPATCH:
 	JP	Z,SIMRTC_SETALM	; SET ALARM 
 	DEC	A
 	JP	Z,SIMRTC_DEVICE	; REPORT RTC DEVICE INFO
-	CALL	SYSCHK
-	LD	A,ERR_NOFUNC
-	OR	A
+	SYSCHKERR(ERR_NOTFUNC)
 	RET
 ;
 ; NVRAM FUNCTIONS ARE NOT AVAILABLE IN SIMULATOR
@@ -68,9 +66,7 @@ SIMRTC_GETBLK:
 SIMRTC_SETBLK:
 SIMRTC_GETALM:
 SIMRTC_SETALM:
-	CALL	SYSCHK
-	LD	A,ERR_NOTIMPL
-	OR	A
+	SYSCHKERR(ERR_NOTIMPL)
 	RET
 ;
 ; RTC GET TIME