I search image with Debian wheezy for M3
- Go grab any Linux image for the M3 from their download page that’s not “BPI-Berryboot (Ubuntu Mate 15.10 w/GPU support)” (this one sucks)
- Mount the 2nd partition, delete everything, grab the wheezy rootfs on the bottom of this page and unpack it on the 2nd partition
- Wait until they really fixed their stuff to get latest kernel and u-boot fixes or grab the BPI-M3 BSP, build the stuff yourself and overwrite the start of the image/SD card as outlined on Github
Afterwards you have a clean Wheezy image for the M3. And that’s the same with any other armhf rootfs for any other Linux distro found on any other place on the net. Since bootloader/kernel/initrd are totally separated from the 2nd partition where the rootfs lives.
It’s that easy. If you want an OS image that doesn’t suck you’ll have to DIY as outlined above.