AttributeError: 'module' object has no attribute 'alloc_extra_fb'


I received the error in the subject link when I ran the 20-Frame-Differencing example openmv/usr/examples/20-Frame-Differencing/ The program halts at line 24.

Anything I can do to fix this? I couldn’t find the error on the forums.

Thanks for your help. Cool product so far, but I am a noob, so I’m stumbling through.

You need to install the latest firmware which was just released. It’s not packaged for download yet though. See the release tab on the OpenMV GitHub.

Thank you. I am not sure what you mean by Release tab though.

I found this folder:

Would I still be able to use the IDE to update the firmware or can it only be done manually?

OPENMV4 folder?


Use either the firmware.bin or OpenMV.dfu file in the OPENMV3 folder. You can use the IDE to update the camera.

So I downloaded those files. However in the IDE, I can’t seem to force it to ask for the DFU.

I read in the hardware setup tutorial that it would prompt me to do so, but my firmware is also up-to-date with 2.6.0 (according the IDE). It does ask me if I want to reset to the release version, but that didn’t seem to go well. I’m still at 2.6.0.

Thanks for your patience!

See Tools->Run bootloader.

That worked. Thank you!

Hi kwagyeman,

I’ve run across the same ‘alloc_extra_fb’ problem trying to use one of the examples on your github,

Is the OPENMV3 folder for the OpenMV M7 cam?
I was looking at the old firmwares, and for example firmware 2.0 has a clear “OPENMV7” folder.

OpenMV 3 is the OpenMV Cam M7. OpenMV 2 is the M4 board, 1 is the oldest OpenMV Cam from 2013 that was never sold commerically. 4 is the upcoming H7 model.

Thank you very much.
The update and python code on the openmv worked right away. Now to get the whole thing working.