Alright now that I have upgraded Nexus 7 to Lollipop I can update this thread once again.
There are probably two ways to update to Lollipop:
1. Install the OTA file from here: [REF] Nexus 7 Stock OTA URLs | Nexus 7 | XDA Forums and flash it through recovery.
Or if you want a fresh ROM and clean startup, by
2. Get a factory version of the ROM from here: *developers.google.com/android/nexus/images and flash it via Fastboot method using ADB.
I wanted a clean slate, didn't want to have any of the previous dirt that was being stored in the tab after so many app updates and experimentations. So I choose to flash the factory version of Lollipop. Using fastboot method I did following:
1. Took a backup of app + data using Helium app that uses your Wifi connection to take backups wirelessly. I choose only those apps which have some data associated with it. So mostly games which had progress saved which I didn't want to play all over again to reach. The Helium app helped me to take a backup in a single ZIP file that I can later restore after upgrading to Lollipop.
2. Double checked that I didn't need any of the files left on the Tablet. Since I upgraded my phone recently I figured I already migrated lot of stuff from tab to phone.
3. Downloaded factory version of nakasi (code name for N7 2012) (direct link: *dl.google.com/dl/android/aosp/nakasi-lrx21p-factory-93daa4d3.tgz) and matched its MD5 hashcode to be sure that the image isn't corrupt.
4. Extracted the files inside that image file (named "nakasi-lrx21p-factory-93daa4d3.tar") using 7-zip. Again extracted the extension less file that came out from the tar file (named "nakasi-lrx21p-factory-93daa4d3"). This got me these files:
bootloader-grouper-4.23.img
flash-all.bat
flash-all.sh
flash-base.sh
image-nakasi-lrx21p.zip
I would just need first (img) and last (zip) file to upgrade to Lollipop since I am using Windows. If you are using Linux you can use the script files (sh). On windows you can also use the script file (bat), but I like to do things manually using ADB shell.
5. So after connecting the N7 with my PC using a USB cable, I fired up ADB shell. Then I used the command adb devices to check if I can communicate with the tab.
6. Well I could communicate (since output of adb devices is in accordance with something like "<device serial number> device"). Then following commands were used to flash the Lollipop and in these order:
> adb reboot-bootloader
> fastboot erase boot
> fastboot erase cache
> fastboot erase recovery
> fastboot erase system
> fastboot erase userdata
> fastboot flash bootloader bootloader-grouper-4.23.img
> fastboot reboot-bootloader
> fastboot -w update image-nakasi-jwr66y.zip
And viola in about 15 minutes I was tasting Lollipop.
. Will post pics later.
You can refer the flashing guide here: [GUIDE] Flashing a Factory Image with fastbo… | Nexus 7 | XDA Forums
- - - Updated - - -
Here are the pics: *minus.com/mQjQNTOaB1Ls4
