CM11 for the Ainol Novo 7 Aurora II

It's been a while since I've used the Ainol, as I have probably five other tablets lying around. The next time I looked at it, Android was complaining about "Encryption unsuccessful". It would boot into custom recovery, do some wipe, and boot back into the same error message. The Ainol Novo 7 Aurora II has been running CM10.2. I reckon it's time to upgrade it to CM11.

The procedure from the CM11 (4.4.2) thread looks simple enough.

1. Download and install TWRP recovery.
2. Copy the CM11 ROM, gapps, and compatibility zip onto the microSD card (and insert into tablet).
3. Power on tablet while holding down the VOL- button.
4. Once booted to the custom recovery, enter "Wipe" menu and swipe to perform a factory reset.
5. Flash/Install the ROM, gapps, and compatibility zip.
6. Select "Reboot system".

Did the normal wipe, but TWRP unable to mount /data partition. So, I did a "Format data", then used "Advanced wipe" to wipe everything except the SD-ext. Did another wipe/factory reset, and this time it didn't complain. So, there's a new boot animation, which is a good sign. And the Cyanogenmod logo started spinning, and it kept on spinning for the next 10 minutes. That can't be right. Did another flash with the same results. Went back to the tried and tested CM10.2. Same spinning logo.

This time even Format Data is giving me I/O errors. And seems like the partitions are in ext3 instead of the expected ext4. Something must have gone terribly wrong. The tablet is as good as bricked. As a last resort, I turned to the Aurora II Unbrick Kit 2.0.

Instructions to prep the kit:

1. Run USB Image Tool as administrator to flash the microSD card.
2. Choose "Device Mode" in the drop-down menu.
3. Choose your microSD card on the left panel.
4. Click the "Restore" button.
5. Choose "Aurora II 0607 Image.img" in the pop-up window, then click Ok.
6. Wait until the image recovery is finished.

At this point you'll have a 500MB microSD card with 4 files:

• factory_update_param.aml
• g06refe3-ota-eng.chengnan.tan.zip
• u-boot.bin
• uImage_recovery

To continue:

1. Insert the prepared microSD card into your tablet.
2. Connect the power adapter to your tablet.
3. Turn the tablet on by pressing "Power" and "Volume -" simultaneously.
4. Wait until the auto-update is finished, at which point the tablet will reboot.
5. Remove the microSD card prior to next boot or else tablet will be flashed again.

In my case, flash was completed, but tablet still refuses to boot up properly. Next step is to copy the aml_autoscript to the microSD card and repeat the flash. The "aml_autoscript" is a NAND scrubbing tool to format your internal memory. Note that the forums advise using aml_autoscript as a last resort.

This time, the tablet was able to boot up (to the Chinese ROM) after the flash. With the confidence knowing I can recover from a bad/corrupted/incorrect partition, I proceeded to install Troy's CM11.

First step was to install the TWRP recovery to NAND (via the microSD card). The stock Android recovery gives me an error about invalid/wrong signature, plus the ff. errors:
E:Bad bootloader arguments
"(null)"
E:unknown volume for path [/udisk/factory_upgrade_param.aml]
E:Can't mount /udisk/factory-update-param.aml

No matter; there's more than one way to skin a cat. Simply extract uImage_recovery from the TWRP zip and copy to the root directory of the microSD card, then try again. This time, the tablet booted into TWRP instead of the stock Android recovery. Just to be sure that the partitions are all good and clean:

1. "Wipe" "Format Data"
2. "Wipe" "Advanced Wipe"  "System", "Cache", and "Dalvik Cache"
3. "Wipe" "Factory Reset"

...then flash these zips (in order):

• TWRP-v2.6.0.0-aurora2_elf2_crystal-ext4.zip
• cm-11-20140716-UNOFFICIAL-elf2.zip
• gapps-kk44-core-amlogic.zip
• aurora2-cm11.0-multiuser_compatibility-rc1.zip

All good!