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.

Full Clean Wipe

When upgrading Android devices from one ROM to another ROM, or from one version to another (e.g. Ice Cream Sandwich to Jelly Bean), it's best to do a full wipe. Me, I always do a full wipe just the same to be sure that the new ROM works well with no artifacts from the previous ROM.

For of all, do a backup from the recovery. Obviously, make sure you have enough disk space (and battery power) to complete the operation.

1. Under Mount & format, do a format system.
2. Then format data.
3. Then format cache.
4. Go back to the main menu, then wipe data/restore.
5. Then wipe cache partition.
6. Go to Advanced, then wipe Dalvik cache.
7. At this stage, you can proceed to flash your new ROM.
8. Reboot, then proceed to flash gapps and other zips you want.
9. Reboot again.

CJK Character Support on Kobo Mini

Extending the Kobo Mini to support CJK characters is as easy as installing the correct CJK fonts. Simply create a folder called fonts in the root directory of the Kobo, then copy in the CJK fonts from Windows. Heck, go crazy and copy in as many TrueType fonts as you want (don't forget Comic Sans) to extend the built-in library of eight fonts. With this trick, I'm now able to read my Chinese epubs.