Guys, problem with the new update 4.1.2. I click ok to update OTA, after that asked to reboot. After reboot, phone become like a stock phone, lost all phone numbers, all apps, all message. Like brand new phone. Somehow the version still maintain 4.1.1. Right now my most important thing is to recover back my contacts. How can that be done? Especially i have contact that I recently got just 2 weeks before the OTA update.

Guys, i'm on 4.1.1. Then i got the message system update, i think it's for 4.1.2. I click update now, immediately the phone reboot. once reboot, it goes to clockwork mode. And it got stucked there with all the options like (reboot system now, install from sd card, wipe data/factory reset, xxx etc). At the bottom, got message saying :

Finding update package...
opening update package...
verifying update package...
E: failed to verify whole-file signature
E: signature verification failed
Installation aborted.

How to solve this?

Eh, i didn't know i'm using custom things. When i update to 4.1.1 it was OTA. Anyway, to prevent future problems, (if I am really on any custom things now) is there anyway I can go to stock ROM? Hope somehow there is a way.

I did use Gnex toolkit (with bigxie something that was posted on the first page of galaxy nexus thread back in July or August) to update to 4.1. But when the official came out, i downgrade it to ICS 4.0, and used the OTA update to go to 4.1.1. My intention was to make life easier in the future so that I can just OTA. But right now I am having problem to OTA to 4.1.2. So i just hope there is a way to make everything back to stock standard so that future upgrade with OTA will be no problem. Is there any way?

Thanks. It worked. Just to detail out to those who faced similar problem. What i did was

1. Install latest Gnex toolkit v9.0
2. Launch it, choose the version of my Nexus which is option 6, android 4.1.1 (build JR03C)
3. Choose option 6 (Flash recovery (CWM Touch, TWRP Touch or Stock)
4. Choose option 3 (Flash Stock Recovery)
5. Put my phone into Fastboot mode and click continue
6. Once done it will auto reboot to phone
7. I then go to Settings>Apps>All>Google Services Framwork and click clear data
8. Go to settings>about phone>update and click check update
9. It shows update to 4.1.2 available and now I am able to do OTA update to 4.1.2.

Thanks again to Vernon. I hope with this I have go back to stock rom and in the future update I can still do OTA.

Vernon, are you saying CWM would render the phone not being stock? So if anyone using the Gnex toolkit and choose the option 1 click for all (unlock, root, etc etc) it will make the phone not stock rom and will have issue with future OTA?