The T-Mobile LG G2x P999 officially came out running Android 2.2 Froyo but later was upgraded to Android 2.3 Gingerbread. Neither the sweet Android 4.0 Ice Cream Sandwich nor the chewy Android 4.1 Jelly Bean official updates made it to the phone — at least not officially.

With the help of independent developers, the latest Android treats have been ported to the phone and can be enjoyed via popular custom ROMs such as CyanogenMod and AOKP.

Recognized XDA Developers  member Benee has successfully compiled a CyanogenMod 10 ROM for the T-Mobile LG G2x LGP999. Flashing this ROM will let you enjoy the delightful treats of Android 4.1 Jelly Bean on your phone. But, delightful as it seems, the ROM still faces some issues, such as:

• Project Butter
• Video playback
• Camcorder
• Hardware acceleration

If you're okay with those lacking features, go ahead and try this custom ROM on your mobile phone.

In this guide, learn how to upgrade the LG G2x P999 to Android 4.1.1 Jelly Bean via CyanogenMod 10 (unofficial).

Warning

• The instructions in this guide are intended for use with the T-Mobile LG G2x, model number LGP999. Applying these instructions on another device or model may produce undesired outcomes.
• The information in this guide is provided for instructional and educational purposes only. There is no guarantee that these instructions will work under your specific and unique circumstances.
• Use these instructions at your own risk. We shall not hold any responsibility or liability for whatever happens to you or your device arising from your use of the info in this guide.
• Read and understand the whole guide first before actually performing the instructions.

Requirements

• T-Mobile LG G2x LGP999 with ClockworkMod Recovery installed
• Download the following:
  • CyanogenMod 10 ROM for the P999 (cm-9.9.9-JB-p999-2.zip, md5sum: d4807f2835b955ebc2de43a51dccd72e)
    • Main Link
      
    • Mirror Link
  • Jelly Bean GApps (Google Apps) package (gapps-jb-20120726-signed.zip, md5sum: f62cfe4a827202899919fd932d5246d7)
• Backup all personal data on your phone to make sure you have a copy of your personal data (e.g., contacts, SMS, MMS, Internet settings, Wi-Fi passwords, and the like) in case the procedure in this guide erases such data.
  • For backup tips, check our guides on how to sync your data to the cloud and how to create local backups of your mobile data.

Instructions

1. Copy the CyanogenMod 10 ROM and the Jelly Bean GApps package to your phone's external SD card.
2. Switch off your phone.
3. Reboot your phone into ClockworkMod Recovery Mode. You can do that by pressing and holding down the Volume Down key and the Power button simultaneously until recovery boots.
4. Create a NANDroid backup of your current ROM. From the main recovery menu, select Backup and Restore and select Backup on the next screen. Wait until the backup process is done.
5. Go back to the main menu and perform a full wipe:
   • Select Wipe data/factory reset and confirm the action on the next screen.
   • Select Wipe cache partition and confirm the action on the next screen.
   • Go back to the main menu and select Advanced. From there, select Wipe Dalvik cache and confirm the action on the next screen.
6. Go back to the main menu and select Install ZIP from external SD card.
7. Select Choose ZIP from SD card and locate the cm-9.9.9-JB-p999-2.zip file. Confirm the action on the next screen to flash the ROM to your mobile phone.
8. Return to the main menu and flash the Jelly Bean GApps package in the same manner as in steps 6 and 7.
9. Go back to the main menu and select Reboot system now to restart your phone.

Congratulations! You have successfully updated your T-Mobile LG G2x P999 to Android 4.1.1 Jelly Bean via the CyanogenMod 10 ROM.