# Frame buffer overflow! How to adjust the Frame buffer without changing the code **URL:** \ **Category:** OpenMV Boards\ **Created:** [April 12, 2026, 11:34am UTC](https://forums.openmv.io/t/frame-buffer-overflow-how-to-adjust-the-frame-buffer-without-changing-the-code/11593 "2026-04-12T11:34:42Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![tangtang](https://avatars.discourse-cdn.com/v4/letter/t/b38774/32.png) [@tangtang](https://forums.openmv.io/u/tangtang)\ **Post date:** [April 12, 2026, 11:34am UTC](https://forums.openmv.io/t/frame-buffer-overflow-how-to-adjust-the-frame-buffer-without-changing-the-code/11593/1 "2026-04-12T11:34:42Z")
I downloaded the firmware from [OpenMV · GitHub](http://github.com/openmv) for openmv4,and copied the main.py to the disk,The program is running normally. but to freeze scripts to do the following: 1 Add the boot.py to the libraries folder. 2 Edit the manifest.py in the boards/OPENMV4,adding freeze (“$(OMV\_LIB\_DIR)/”, “boot.py”) to the manifest.py file 3 generate the firmware image for your OpenMV Cam. when use diy firmware,I got the error message from uart,“Traceback (most recent call last): File “boot.py”, line 85, in RuntimeError: Frame buffer overflow, try reducing the frame size. OpenMV 5fb041dc9a; MicroPython 7c5ab76686; OPENMV4 with STM32H743，” How to adjust the Frame buffer of the openmv4 without changing the code from sensor.VGA to sensor.QVGA? the codes of the boot.py is below: `import sensor, time` `sensor.reset()` `sensor.set_pixformat(sensor.GRAYSCALE)` `sensor.set_framesize(sensor.VGA)` `sensor.skip_frames(time=200)` `clock = time.clock()` `def find_light_spots(img):` `blobs = img.find_blobs([(200, 255)],` `area_threshold=20,` `merge=True,` `margin=2` `)` `lastBlobs = ` `for blob in blobs:` `if (blob.area() < 400):` `if blob.roundness() > 0.4 and blob.density() > 0.5:` `lastBlobs.append(blob)` `detected = ` `if len(lastBlobs) >= 1:` `lastBlobs.sort(key=lambda b: b.area(), reverse=True)` `detected = [(b.cx(), b.cy()) for b in lastBlobs[:min(2, len(lastBlobs))]]` `return detected` `def show_debug_info(img, spots):` `img.draw_string(5, 5, f"blob Num {len(spots)}“, color=255, scale=2)` `if len(spots) == 0:` `return` `colors = [255, 200]` `for i, (u, v) in enumerate(spots):` `img.draw_circle(int(u), int(v), 6, color=colors[i])` `img.draw_string(int(u)+5, int(v)-20, f"P{i}”, color=255)` `img.draw_string(5, 20+15`_`i, f"P{i}: ({spots[i][0]}, {spots[i][1]})“, color=200, scale=fontScale)` `try:` `while True:` `img = sensor.snapshot()` `spots = find_light_spots(img)` `if debug:` `show_debug_info(img, spots)`_ `except KeyboardInterrupt:` `print(“\nsystem is stopped”)` ---
**Author:** ![falthaus](https://avatars.discourse-cdn.com/v4/letter/f/91b2a8/32.png) [@falthaus](https://forums.openmv.io/u/falthaus)\ **Post date:** [April 12, 2026, 4:03pm UTC](https://forums.openmv.io/t/frame-buffer-overflow-how-to-adjust-the-frame-buffer-without-changing-the-code/11593/2 "2026-04-12T16:03:00Z")
Hi I had the same issue with using grayscale VGA on the H7 a while ago. Seems the framebuffer architecture has been changed in a way that uses more memory now, which the H7 doesn’t have. See details here: [V4.8.1. breaking VGA on H7](https://forums.openmv.io/t/v4-8-1-breaking-vga-on-h7/11475) And this is the commit with the changes I’ve implemented on my fork to fix it: [Changed to fixed 1 byte/pixel framebuffer for H7 · falthaus/openmv@a004937 · GitHub](https://github.com/falthaus/openmv/commit/a00493763abb96f5b59288f976fd0bd8b3ff8bab) Maybe this helps Felix ---
**Author:** ![kwagyeman](https://yyz1.discourse-cdn.com/flex029/user_avatar/forums.openmv.io/kwagyeman/32/4_2.png) [@kwagyeman](https://forums.openmv.io/u/kwagyeman)\ **Post date:** [April 12, 2026, 7:24pm UTC](https://forums.openmv.io/t/frame-buffer-overflow-how-to-adjust-the-frame-buffer-without-changing-the-code/11593/3 "2026-04-12T19:24:21Z")
I’ve made a bug tracker for this issue: [Examine if using 1bpp is possible with new CSI FB Arch. · Issue #3103 · openmv/openmv · GitHub](https://github.com/openmv/openmv/issues/3103) It might not be possible, but I will examine if it’s fixable. Note that this may not make it into the V5.0.0 release. ---
**Author:** ![kwagyeman](https://yyz1.discourse-cdn.com/flex029/user_avatar/forums.openmv.io/kwagyeman/32/4_2.png) [@kwagyeman](https://forums.openmv.io/u/kwagyeman)\ **Post date:** [April 13, 2026, 4:57am UTC](https://forums.openmv.io/t/frame-buffer-overflow-how-to-adjust-the-frame-buffer-without-changing-the-code/11593/4 "2026-04-13T04:57:43Z")
I found an easy way to fix this with the new csi API: [modules: Add raw\_bpp control from py\_csi\_ng. by kwagyeman · Pull Request #3104 · openmv/openmv · GitHub](https://github.com/openmv/openmv/pull/3104) ---
**Author:** ![tangtang](https://avatars.discourse-cdn.com/v4/letter/t/b38774/32.png) [@tangtang](https://forums.openmv.io/u/tangtang)\ **Post date:** [April 13, 2026, 7:26am UTC](https://forums.openmv.io/t/frame-buffer-overflow-how-to-adjust-the-frame-buffer-without-changing-the-code/11593/5 "2026-04-13T07:26:54Z")
thanks for your reply,It’s perfect. ---
**Author:** ![tangtang](https://avatars.discourse-cdn.com/v4/letter/t/b38774/32.png) [@tangtang](https://forums.openmv.io/u/tangtang)\ **Post date:** [April 13, 2026, 7:28am UTC](https://forums.openmv.io/t/frame-buffer-overflow-how-to-adjust-the-frame-buffer-without-changing-the-code/11593/6 "2026-04-13T07:28:50Z")
> [@falthaus](#): > > Changed to fixed 1 byte/pixel framebuffer for H7 thanks for your reply,I changed 1byte/pixel for my H7