An unofficial AOKP Jelly Bean ROM for the HTC Desire GSM was released by XDA Developers member vijendrahs. The custom ROM brings with it all of the stock Android 4.1 Jelly Bean capabilities and features and a bunch of other cool additions that makes it one of the best custom ROMs there is for the HTC Desire. With this new release, you can take it for a spin using your HTC Desire.

Remember though that this is still a ROM that is constantly being updated for new features.  Camera recording, for instance, still doesn't work.  Although, pretty much most of the essentials are already in working order.

This guide shows you how to upgrade the HTC Desire GSM to Android 4.1.1 Jelly Bean via AOKP Jelly Bean custom ROM (unofficial).

Warning

• The instructions in this guide are intended for use with theHTC Desire GSM. 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

• HTC Desire GSM with S-OFF, with ClockworkMod Recovery installed, and running either an ICS-based or Jelly Bean-based ROM
  • For help with custom recovery, see “How to flash ClockworkMod Touch Recovery for the HTC Desire.” 
• Download the following files:
  • AOKP Jelly Bean ROM for HTC Desire (AOKP_VJ_JB_v1.3.zip, 101.92 MB)
  • Google Apps package (gapps-jb-20120726-signed.zip, 83.1 MB)
• Make sure your device's battery still has at least 70% power. You don't want the device to shut down in the middle of the procedure.
• 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 file ROM and Google apps package to your phone's internal SD card.
2. Turn off the phone.
3. Boot into Recovery Mode. To do so, hold Volume Down and Power buttons until the device boots to the bootloader/HBOOT mode. Use the volume keys to highlight the RECOVERY option, then select it using the power button to boot into recovery. In recovery, use the Volume buttons to scroll up and down and the Power button to select options.
4. Create NANDroid backup of your existing ROM. To perform a backup, select Backup and Restore > Backup.
5. Go back to main recovery menu after backup is complete.
6. Select Wipe data/Factory reset and confirm the action on the next screen.
7. Select Install ZIP from SD card > Choose ZIP from SD card.  Select the ROM's ZIP file and confirm that you want to install it.
8. Install the Google Apps package in the same manner as in step 7.
9. Select Reboot system now to restart your phone into the new ROM.  The first boot under the new ROM may take up to 5 minutes.

Awesome! You should now have AOKP Jelly Bean ROM installed on your HTC Desire.