Printed a lot of debug logs and an workaround was found. Please flash the following u-boot.bin.sd.bin.zip (596.4 KB) to your eMMC and see if that helpes. In serial console press Ctrl+C to interrupt u-boot autoboot, then run ums 1 2 to expose eMMC as a USB disk to your host computer. Then run following commands on your host Linux computer (replace sdX with real device):
sudo dd if="./u-boot.bin.sd.bin" of=/dev/sdX bs=1 count=444
sudo dd if="./u-boot.bin.sd.bin" of=/dev/sdX bs=512 skip=1 seek=1
If you cannot get this to work I’ll be back on Monday.