Ainol CM10 to CM10.1

The Ainol Aurora II has been running fine on CM10 (Android 4.1 Jelly Bean) for a while. But with nothing much to do, I've decided to upgrade to CM10.1 (Android 4.2) given that a stable release from Christian Troy is out.

For the upgrade, you'll need:
 - a new TWRP recovery
 - the actual ROM
 - latest gapps
 - compatibility zip for Aurora II

Now, with Android 4.2, you get a multi-user functionality where the tablet may be shared among different users with their own settings, apps, accounts, etc. For that, you'll need to flash a multi-user compatibility zip and a multi-user zip.

So first, copy the TWRP binary and the required zips to the external microSD card. Power on the tablet with Vol- button pressed. The tablet should boot into TWRP.

Format the /system, /data, and /cache partitions. If you're lazy, just select the "factory reset" option. Then, flash the ROM, the gapps, the compatibility zip, and the multiuser zip. Reboot afterwards.

In my case, the tablet didn't come back properly. All I get is a black screen. Turns out you can only use the multi-user feature if the filesystem is ext4. I believe my one is still the stock UBIFS. Another round of factory reset. This time I flashed the ROM, gapps, and the normal compatibility zip for Aurora II. This time the tablet came up properly.