Can I rollback the stock system by just installing an older image zip?

Question

I received the 4.2.x updates on my Nexus 7 and the performance has been awful. I tried the Forever Gone hack and it helped but it's still much worse than 4.1.x. I'm not so excited about doing a factory wipe in order to make my system almost as good as it was a month ago.

I've never tried rolling back a stock system before, is it possible to download the official nexus image zip and install it from CWM recovery? Or do I have to do a more involved wiping and flashing process? My system is stock 4.2.1 rooted and unlocked, with custom recovery.

Answer 1

Don't use full image at recovery! It contains recovery too (CM can repair itself, but reflash of bootloader is not needed).

Use fastboot and flash partitions: system, data

You will lose all of your data on the tablet, but it is needed because of the different filesystem structure. Without reflashing data you will get a bootloop.

Answer 2

You will most probably have to wipe.

This is because the data will have a different structure, as it is a major version.

If you have recovery, you can flash it to see if it works and if it doesn't, then you can wipe it.

I would suggest backing up any data you would like to keep.