Thấy bác cũng có vô hỏi trong xda.deverloper mà,up rom từ thẻ nhớ đây này:
(cái này chắc bác cũng đọc được nhỉ? thấy hỏi bằng tiếng Anh rất pro

1. OPEN RUU_Excalibur.exe with an archiver and extract files to temporary directory (the file we want is the EXCAIMG*.nbh)
2. Format SD card using FAT32
3. Insert SD card into phone
4. Connect using ActiveSync
5. Rename nbh file to "EXCAIMG.nbh"
6. Copy EXCAIMG.nbh to SD card
7. Disconnect phone
8. Start Manual Bootloader (hold camera key for three seconds and press power button)
9. After quick messages (checking sd card, etc.) you should get "Update SD image? Press power button to download" screen with countdown in bottom corner
10. After timeout you will go to color bars UI
Exit bootloader: hold camera key, wait three seconds and hold down power key also until phone turns off
My phone is not unlocked, so I didn't test with other roms.