Jelly Bean (Android 4.1) released for AT&T HTC One X .... but how to install it on unlocked AT&T phone? Though there are few questions already existing about AT&amp;T HTC One X in the forum but this one is a bit different.

AT&amp;T has recently released long awaited Jelly Bean update for HTC One X.
But when I am trying to update the software on my phone using Settings --> AT&amp;T Software Update, nothing happens.

I have read that other users are also experiencing this problem and this is probably due to phone being Unlocked!

Moreover, I have read that normal Jelly Bean ROM cannot/shouldn't be installed on AT&amp;T HTC One X as the specification of AT&amp;T's model is different.

Can anyone please tell us how to update software on our Unlocked phones? Thanks!
Manually backup all the data with the help of below mentioned steps so as to make sure that just in case if the data gets lost or corrupted, the same can be restored with the help of below mentioned steps. Make sure that you don’t use any sorts of PC Suites like HTC Sync to back up the data as it won’t help you restore the data smoothly.  

SMS – Use “SMS Backup &amp; Restore app”
Contacts – Sync with the Gmail application
Call Log -Call Log and Restore
Images, Songs, Videos, Files – Copy to internal / External SD Card
APN and MMS Settings – Note down from the path “Applications > Settings > Wireless and Network > Mobile Networks > Access Point Names”

Enable the USB Debugging from the path “Settings > Applications > Development > USB debugging”
Make sure that the minimum battery life should be 30% so as to ensure that the phone doesn’t get turned Off in the middle of update.
Disable / uninstall all the security suites installed in your phone.

Let’s head to the procedure which will help you update your phone with the latest firmware of Jellybean 4.1 firmware.

Procedure to Update AT&amp;T HTC One X with Jellybean 4.1 firmware:


  1.Download the Official Jellybean 4.1 Firmware update from here to your computer.
  Once downloaded, you need to place the same in your device’s root or in the phone’s storage and not in any of the sub folders.  
  
  2.Now, disconnect the device from computer if you have connected the phone and then turn Off the device so that it can be entered in the Recovery Mode.
  To enter HTC One X in the recovery mode, press the Volume Down button and while doing this, press and hold the power button for a period of 10 seconds till you see the fastboot screen.    
  
  3.In Fastboot mode, use the Volume Keys to navigate to the Recovery option and then press the power button. After this, you will see the HTC Logo on the screen and the screen will go blank with an exclamation mark and a triangle.  
  
  4.Now, press and hold both the Volume Up and down key and then while holding them, press and release the power button. After releasing the Volume rocker key, you will get a Blue Menu along with a set of options which will indicate that the device has been successfully landed in the Recovery Mode.  
  
  5.Now, select “Apply update from internal storage” from the option and press the Power button. You will need to select the update file which you have placed in the Phone storage and press the Power button to confirm the same. It will take around 3 -5 minutes for applying the update and once it’s done, you need to select the option of “Reboot system now” for rebooting the device in the normal mode.


Source

NOTE:Do it at your own RISK, no one can held responsible.