I have a custom Android 5.1 build and I can flash this to an older T3 Plus board and it runs.

When I try to do the same on any newer board (I have 6 of them doing the same) it reports "Failed to load BL33" in the debug output.

Both boards are marked with the same revision number. The only difference I can see is that the board RAM part number is different but I would expect backward compatibility. I have checked the u-boot source on Github and there are no updates indicating any changes for newer version boards.

If I download a ready-made image from the FA website it works but sadly, the display orientation is wrong and I also don't have access to serial ports and GPIO with that image.

Anyone know what the BL33 failed message indicates?