Hi, I hard bricked my ASUS Transformer TF300T (my fault) and sent it to ASUS to repair it. They replaced motherboard. So now I have it back with fresh Android 4.1.1. I tried to use ASUS' app to unlock bootloader (stock ROM without root is not usable for me), but when I agree and tap to "unlock", it only says "unknown error" and it doesn't work. It also says it might be problem with network, but network is working correctly. I think the problem is related to replacement of motherboard, but I don't know how. Does anyone have same problem? Some advice? Thanks in advance...