diff --git a/src/defs.h b/src/defs.h
index 41a0774b..7e88aca1 100644
--- a/src/defs.h
+++ b/src/defs.h
@@ -117,6 +117,7 @@
 #define SCREEN_START         0x1E000000   // start of screen area
 #define SCREEN_SIZE          0x02000000   // size of screen area
 #define CACHED_SCREEN_OFFSET 0x01000000   // offset to cached screen area
+#define WARN_12BIT                        // warn that 9bpp & 12bpp won't work
 #define HIDE_12BIT_PROFILES               // 12 bit profile won't work on Pi zero2 etc
 //#define INHIBIT_DOUBLE_HEIGHT           // inhibit line doubling as it causes memory stalls
 //#define USE_ALT_M7DEINTERLACE_CODE      // uses re-ordered code for mode7 deinterlace
@@ -129,6 +130,7 @@
 #define SCREEN_START         0x1E000000   // start of screen area
 #define SCREEN_SIZE          0x02000000   // size of screen area
 #define CACHED_SCREEN_OFFSET 0x01000000   // offset to cached screen area
+#define WARN_12BIT                        // warn that 9bpp & 12bpp won't work
 #define HIDE_12BIT_PROFILES               // 12 bit profile won't work on Pi zero2 etc
 //#define INHIBIT_DOUBLE_HEIGHT           // inhibit line doubling as it causes memory stalls
 //#define USE_ALT_M7DEINTERLACE_CODE      // uses re-ordered code for mode7 deinterlace
diff --git a/src/rgb_to_fb.S b/src/rgb_to_fb.S
index e1348f25..c371d98b 100644
--- a/src/rgb_to_fb.S
+++ b/src/rgb_to_fb.S
@@ -2226,14 +2226,15 @@ wait_capture_count:
         beq    wait_capture_count
         ldr    r12, write_pointer
 core_capture:
-        ACTUAL_WAIT_FOR_PSYNC_EDGE_FAST                // expects GPLEV0 in r4, result in r8
-        str    r12, write_pointer                      // write pointer is one sample behind
-        str    r8, [r12], #4
-        sub    r11, r11, #1
-        cmp    r11, #0
-        bgt    core_capture
-        str    r12, write_pointer                      // final write pointer
-        mov    r11, #0
+        ldr    r8, [r4]
+        eor    r0,r8, r3					// ***adjust register so r8 isn't corrupt
+        tst    r0, #PSYNC_MASK
+        streq    r12, write_pointer
+        eoreq    r3, #PSYNC_MASK
+        streq    r8, [r12], #4
+        subeqs    r11, r11, #1
+        bne    core_capture
+        str    r12, write_pointer           // final write pointer
         str    r11, sync0_flag
         str    r11, sync1_flag
         str    r11, capture_count
diff --git a/src/rgb_to_hdmi.c b/src/rgb_to_hdmi.c
index 310baaf4..a926f5e9 100644
--- a/src/rgb_to_hdmi.c
+++ b/src/rgb_to_hdmi.c
@@ -3250,7 +3250,7 @@ void rgb_to_hdmi_main() {
                                  }
                                  osd_set(1, 0, osdline);
                              } else {
-#if defined(RPI2) || defined(RPI3)
+#if defined(WARN_12BIT)
                                  if (capinfo->sample_width >= SAMPLE_WIDTH_9LO) {
                                     osd_set(1, 0, "9/12BPP UNSUPPORTED on Zero2W, use Zero/W");
                                  } else {
@@ -3298,7 +3298,7 @@ void rgb_to_hdmi_main() {
             ncapture = osd_key(OSD_SW3);
          }
 
-#if defined(RPI2) || defined(RPI3)
+#if defined(WARN_12BIT)
          if (powerup || ((capinfo->sample_width >= SAMPLE_WIDTH_9LO) && !osd_active())) {
 #else
          if (powerup) {
@@ -3318,7 +3318,7 @@ void rgb_to_hdmi_main() {
                }
                osd_set(0, ATTR_DOUBLE_SIZE, osdline);
                osd_display_interface(2);
-#if defined(RPI2) || defined(RPI3)
+#if defined(WARN_12BIT)
                if(capinfo->sample_width >= SAMPLE_WIDTH_9LO) {
                   osd_set(2 + 4, 0, "9BPP & 12BPP NOT SUPPORTED on Pi Zero 2W");
                   osd_set(2 + 5, 0, "Please use a Pi Zero or Pi Zero W");