"MemoryError: Out of fast Frame Buffer Stack Memory!" after M7 update

I’m new to the nice OpenMV ecosystem. I started to play with it. I hadn’t issues since the update of the IDE (up to 2.5.1) and then the firmware of my M7 camera.
Script like that one was running nice before the update:

import sensor, image, time

sensor.reset()                      # Reset and initialize the sensor.
sensor.set_pixformat(sensor.RGB565) # Set pixel format to RGB565 (or GRAYSCALE)
sensor.set_framesize(sensor.QVGA)   # Set frame size to QVGA (320x240)
sensor.skip_frames(time = 2000)     # Wait for settings take effect.
clock = time.clock()                # Create a clock object to track the FPS.

    clock.tick()                    # Update the FPS clock.
    img = sensor.snapshot().lens_corr(strength=1.7)         # Take a picture and return the image.
    print(clock.fps())              # Note: OpenMV Cam runs about half as fast when connected
                                    # to the IDE. The FPS should increase once disconnected.

now by using


, I got:

MemoryError: Out of fast Frame Buffer Stack Memory!

This might be related to an issue another use was happening. I will debug tonight and post a firmware fix.

I just started using the Cam H7 and I noticed the same issue. It happens in many of the example programs, such as find_apriltags and find_rects.
Do you think this will be a quick fix? If not, I’d like to roll back my firmware. Is there a list of compiled binaries somewhere, or do I have to build it myself? Which commit would I have to go back to so I can avoid this error?

I already fixed it, we just need to test this and then I’ll make another patch release today.

Is there a procedure to rollback the firmware?
I would like to be prepared the next time there is a bug. Maybe I would like to make the camera working properly quickly and not waiting for a fix although I know you are fast to answer issues.
The more products you will have, the more fragmented will be the code.

Yes, you can download any older release from here:

BTW we fixed the issue and there should be an udpate.

Thanks for that update! Just by coincidence, last night I pulled my M7 off the shelf again for the first time in months, and was really confused when I couldn’t get it to detect apriltags anymore.


The new firmware will be downloaded by the IDE.