Originally Posted by tianqi
Let me double check the steps before i try the third time
flash chinese update.acer.zip renaming it to update.zip...
Boot into it, using dd and restore the old 1.016.04 system.img, flexrom.img and boot.img.
And rename the extracted official 1.139.04 update to update.zip to flash?
I would recommend rebooting each time after installing system.img and flexrom.img (especially system.img, the tablet usually crashed after finishing flashing).
Prepare your update.zip on the microSD. The update.zip is the file you extract after you decode (XOR 12 on the file contents using a hexeditor) one of the update packs posted around.
NOTE: If you cannot open the .zip you want to pass for an update.zip, that's the file you need to XOR 12 (DO NOT rename this file to update.zip - there should be no renaming files involved). After you decode it, inside it you will find an update.zip, another folder and a file. That's the update.zip you need to place on the microSD.
After that flash boot.img, and power down. Power up holding the volume button closest to the power button and enter recovery. The update should complete without issues.
If you miss entering recovery, you will need to go back to flashing the chinese rom again, the tablet boot will fail with an error about an incorrect checksum.