diff --git a/demos/driven/part20_credits/credits.s b/demos/driven/part20_credits/credits.s
index 64ae74f1..f12e99b5 100644
--- a/demos/driven/part20_credits/credits.s
+++ b/demos/driven/part20_credits/credits.s
@@ -63,6 +63,8 @@ load_loop:
 
 scroll_loop:
 
+	jsr	hgr_vertical_scroll
+
 
 	;============================================
 	; clear lines to get rid of stray old chars
@@ -162,7 +164,7 @@ skip_next_text:
 	; do the scroll
 	;=============================
 
-	jsr	hgr_vertical_scroll
+	jsr	wait_vblank
 
 	jsr	hgr_page_flip
 
@@ -183,8 +185,11 @@ skip_next_text:
 	.include	"../irq_wait.s"
 	.include	"../hgr_page_flip.s"
 
+	.include	"../vblank.s"
+
 
 final_credits:
+	.byte 20," ",0
 	.byte 16,"DRI\/EN",0
 	.byte 20," ",0
 	.byte 15,"by Desire",0
diff --git a/demos/driven/vblank.s b/demos/driven/vblank.s
new file mode 100644
index 00000000..8f0d6ca3
--- /dev/null
+++ b/demos/driven/vblank.s
@@ -0,0 +1,26 @@
+; wait for VBLANK
+
+; no way to do this on II/II+ short of vapor lock / floating bus
+; IIe you can read $C019 (in VBLANK when top bit 0)
+; IIc you can also read $C019 (also can setup interrupt)
+; IIgs you can read $C019 but reverse of IIe (in VBLANK when top bit 1)
+
+
+VBLANK	= $C019		;
+
+	; wait for vblank on IIe
+	; positive? during vblank
+
+wait_vblank:
+	lda	APPLEII_MODEL
+	cmp	#'e'
+	bne	no_vblank
+
+wait_vblank_iie:
+	lda	VBLANK
+	bmi	wait_vblank_iie		; wait for positive (in vblank)
+wait_vblank_done_iie:
+	lda	VBLANK			; wait for negative (vlank done)
+	bpl	wait_vblank_done_iie
+no_vblank:
+	rts