this is a very quick and dirt (as in not too much detail) method...from stock to unlocked, rooted, JB.
this is all off the top of my head so i may have missed something...if you have a question about any steps hit me up via google talk
download Wugs root toolkit
backup any content you want from your nexus's internal memory to your PC (unlocking wipes everything off the device)
http://forums.androidcentral.com/ve...us-root-toolkit-v1-5-2-updated-7-14-12-a.html
install drivers
connect phone with usb debugging checked (settings>developer options) to the PC
backup all your user apps and data with the toolkit to your PC
unlock the bootloader (it is literally clicking a button)(phone should reboot i believe)
i think you have to click something on the phone screen too..just accept it.
root it (it is literally clicking a button)
once rooted, restore your user apps using the tool kit and your other stuff you backed up by dragging and dropping
download ROM manager from the play store
open it up, grant SU permission
install ClockworkMOD recovery (highly suggest using touch recovery, but again it is up to you)
you now have CWM recovery installed
you can use other methods to install it (ADB) or install TeamWinRecovery through another method. it is up to you, but CWM is easy and works every time.
so now you are rooted on stock Software with an unlocked bootloader
power down the device
hold volume up and down and then hold power button (all at the same time)
you will get to the bootloader screen (should say unlocked at the botton) press volume up/down until it says recovery at the top...then press power.
it will now boot into CWM recovery (hopefully)
use up/down volume to navigate and power to select
go to backup/restore
choose backup
and let it run until it is finished.
you now have a backup. of stock OS so if anything goes wrong, boot up the way mentioned above, and choose restore and let it run
reboot the device.
purchase Titanium backup Pro key and download TI backup...its worth it...believe me
open it up, grant SU permission
hit the folder with check mark in upper right corner
and under "backup" hit the RUN button next to "backup all user apps" (NEVER backup or restore system apps)
let it run.
download the JB bootloader (optional but a good idea), JB ROM of your choice, and the GAPPS from the original thread (please verify all MD5 sums before flashing...i useES file explorer>longpress the file>properties>show checksum>check MD5>calculate and make sure they match the numbers from the download page) and place them on your internal memory somewhere (i usually make a folder called A_android and place a ROM,GAPPS,themes,others folder in there to sort everything...its up to you how you want to do it)
backup call logs and SMS messages if you want with apps from the play store
make sure your contacts are all synced with your google account
once you have everything on the internal memory
you can use ROM manager or other apps to boot into recovery (or use the method above)
once you are in CWM recovery
choose
Wipe data factory reset>yes
wipe cache>yes
mounts and storage>format system>yes
install .zip from SD card
navigate to the JB ROM and select it
choose Yes
let it install (~ 3-5 minutes)
then navigate to the GAPPS and choose Yes
let those install (> 1 minute)
chosoe "go back"
reboot device.
let it boot...if it goes for more than 10 minutes you probably did something wrong. either wipe those things again, and reflash the ROM and GAPPS or restore you backup)
once booted you will be on Jelly Bean.
i usually skip signing in at the beginning and just open up the market, sign in there, download titanium and the pro key
open up titanium
grant SU permission
hit the page and check mark thing in the upper right
under "restore"
hit the "RUN" button next to "restore missing apps with data"
and let it run.
once finished, you are going to have to set up your home screens again, and restore your SMS backup and call log backup but everything else should be good to go.
it seems long when typing it out, but it actually takes much longer to type it than do it.
its a pretty painless job, and you can always flash stock fairly easily on a Nexus. so dont fret too much if you screw something up.
jsut read for a solid day or 2 and you should be good.