diff --git a/src/kernal/screen_m65/mega65_chrout_screen.s b/src/kernal/screen_m65/mega65_chrout_screen.s
index 8d771c31..fd122ae1 100644
--- a/src/kernal/screen_m65/mega65_chrout_screen.s
+++ b/src/kernal/screen_m65/mega65_chrout_screen.s
@@ -4,6 +4,6 @@
 
 m65_chrout_screen:
 
-	// Provide implementation
+	// XXX provide implementation
 
-	rts
\ No newline at end of file
+	rts
diff --git a/src/kernal/screen_m65/mega65_clrscr_clrwin.s b/src/kernal/screen_m65/mega65_clrscr_clrwin.s
index a5876e2f..5d363ed6 100644
--- a/src/kernal/screen_m65/mega65_clrscr_clrwin.s
+++ b/src/kernal/screen_m65/mega65_clrscr_clrwin.s
@@ -37,13 +37,14 @@ M65_CLRWIN:
     bpl !-
 
     lda #$0F
-    sta M65_LPNT_KERN+2
+    sta M65_LPNT_KERN+3
     lda #$F8
-    sta M65_LPNT_KERN+1
+    sta M65_LPNT_KERN+2
 
     // Go trough all the rows
 
     phz
+    ldx M65_SCRMODE
     ldy #$00
 
     // FALLTROUGH
@@ -61,7 +62,7 @@ m65_clrwin_loop:
 !:
 	lda #$20
 	sta_lp (M65_LPNT_SCR),z
-	lda #$00
+	lda COLOR
 	sta_lp (M65_LPNT_KERN),z
 	inz
 	cpz M65_TXTWIN_X1
@@ -71,12 +72,30 @@ m65_clrwin_loop:
 
 m65_clrwin_loop_next:
 
+	// Increment M65_LPNT_SCR and M65_LPNT_KERN by the row length
+
+	clc
+	lda m65_scrtab_txtwidth, x
+	adc M65_LPNT_SCR+0
+	sta M65_LPNT_SCR+0
+	bcc !+
+	inc M65_LPNT_SCR+1
+!:
+	clc
+	lda m65_scrtab_txtwidth, x
+	adc M65_LPNT_KERN+0
+	sta M65_LPNT_KERN+0
+	bcc !+
+	inc M65_LPNT_KERN+1
+!:
+	// Increment row counter, check if new row is valid
+
 	iny
-
-    // XXX
-
+	cpy M65_TXTWIN_Y1
+	bne m65_clrwin_loop
     plz
 
+    // Set screen variables
 
 	// XXX implement this
 
diff --git a/src/kernal/screen_m65/mega65_scrmodeset.s b/src/kernal/screen_m65/mega65_scrmodeset.s
index 1ee6e0ac..c7e070e5 100644
--- a/src/kernal/screen_m65/mega65_scrmodeset.s
+++ b/src/kernal/screen_m65/mega65_scrmodeset.s
@@ -42,6 +42,13 @@ m65_scrmodeset_internal: // entry point for M65_MODE65
 
 	sta M65_SCRMODE
 
+	// Set flags/variables for 40/80 columns and 25/50 rows
+
+	tax
+
+	lda m65_scrtab_vic_ctrlb,x
+	sta VIC_CTRLB
+
 	// Set the base screen addresses:
 	// - in VIC_SCRNPTR and M65_SCRTXTBASE to $16000
 	// - in VIC_COLPTR to $0000
@@ -60,11 +67,4 @@ m65_scrmodeset_internal: // entry point for M65_MODE65
 	stx VIC_SCRNPTR+1
 	stx M65_SCRTXTBASE+1
 
-	// Set flags/variables for 40/80 columns and 25/50 rows
-
-	tax
-
-	lda m65_scrtab_vic_ctrlb,x
-	sta VIC_CTRLB
-
 	rts