Why did you flash the bootloader?
I don't think there was ever a bootloader update for et7100 v2 for it to be released.
When I get mine, I can try to read the bootloader if it's possible and post it here.
USB flash wasn't working, and also it didn't booted when a flash was inserted (even a empty one)...
I've tried the Serial debugging and always when a flash stick was inserted in one of the USB ports it will throw an exception and say "rebooting" but stuck there...
I thought reflashing the bootloader would solve that, didn't paid enough attention though... and it is bricked now, the bootloader doesn't seem to exist anywhere no more...