[Samsung Galaxy Nexus] efrant:
[HOW-TO] Install official JRN84D (Jelly Bean 4.1) on your GSM Galaxy Nexus

Ok, given that I like to do things my way and then show others how I did it for learning purposes, here is my take on how to flash JRN84D (official) on ANY maguro (i.e., GSM/HSPA) Galaxy Nexus, regarless of what build you are currently running.

Notes:

1) Doing it this way will leave you with an official JRN84D ROM, and you will receive future updates, assuming that there are any for JRN84D (which is almost certainly the case).

2) Method 2 assumes that you have: a) the drivers properly installed, b) an unlocked bootloader, and c) you have downloaded the attachment in the first post of this thread.

3) Both these methods will require you to wipe your data, but NOT the files you have in /sdcard. (I tried to get it to work without wiping data, but I couldn't get it to work. This is not to say that it won't work for all of you, but I can guarantee that it will work if you wipe.) The Play Store will automatically re-install all your apps, and your can restore the app data with Titanium Backup (root required of course).

4) I have had NO issues whatsoever so far with the OS. There are some apps, however, that are not compatible with Jelly Bean.

Method 1: CWM recovery already installed

1) Download takju JRN84D from here (this is Koush's repack) to your computer and rename (or delete) this file: /system/etc/install-recovery.sh. Use 7zip to do this, not WinZip or WinRar or whatever.

2) Move the file to /sdcard on your phone.

3) Download the CWM-flashable version of the XXLF1 radio from here and the CWM-flashable version of the LC03 bootloader from here to /sdcard.

4) Backup your app data using Titanium Backup. Root is required for this step. Alternatively, if you do not have root, you could try using this, but no guarantees it will work.

5) Reboot your phone into CWM.

6) Select "wipe data/factory reset" and select "Yes -- delete all user data"

7) Select "wipe cache partition" and select "Yes - Wipe Cache"

8) Select "advanced" and select "Wipe Dalvik Cache" and select "Yes - Wipe Dalvik Cache"

9) Select "*****Go Back*****" to return to the main menu

10) Select "install zip from sdcard" and select "choose zip from sdcard" and navigate and select the bootloader file you downloaded, and flash it.

11) Select "install zip from sdcard" and select "choose zip from sdcard" and navigate and select the radio file you downloaded, and flash it.

12) Select "install zip from sdcard" and select "choose zip from sdcard" and navigate and select the JRN84D file you downloaded, and flash it.

13) Optional -- If you want root, flash the attachment the same way. (This is Chainfire's SuperSU.)

14) Go back to the main menu and select "reboot system now".

15) Done! Enjoy stock Jelly Bean 4.1

Method 2: Stock recovery installed

1) Download CWM from here to the same directory on your computer as your fastboot file, and rename it to cwm.img.

2) Download takju JRN84D from here to /sdcard on your phone. (This is Koush's repack.)

3) Download the CWM-flashable version of the XXLF1 radio from here and the CWM-flashable version of the LC03 bootloader from here to /sdcard.

4) Backup your app data using Titanium Backup. Root is required for this step. Alternatively, if you do not have root, you could try using this, but no guarantees it will work.

5) Reboot your phone into fastboot mode (turn off and press vol up + vol down + power) and plug into your computer.

6) Open a command prompt in the same directory as your fastboot file and type: fastboot boot cwm.img

7) On your device, CWM should be booted up. You can unplug your device from your computer if you wish. From now on, everything is done on your device.

8) Select "wipe data/factory reset" and select "Yes -- delete all user data"

9) Select "wipe cache partition" and select "Yes - Wipe Cache"

10) Select "advanced" and select "Wipe Dalvik Cache" and select "Yes - Wipe Dalvik Cache"

11) Select "*****Go Back*****" to return to the main menu

12) Select "install zip from sdcard" and select "choose zip from sdcard" and navigate and select the bootloader file you downloaded, and flash it.

13) Select "install zip from sdcard" and select "choose zip from sdcard" and navigate and select the radio file you downloaded, and flash it.

14) Select "install zip from sdcard" and select "choose zip from sdcard" and navigate and select the JRN84D file you downloaded, and flash it.

15) Optional -- If you want root, flash the attachment the same way. (This is Chainfire's SuperSU.)

16) go back to the main menu and select "reboot system now".

17) Done! Enjoy stock Jelly Bean 4.1.