Installing Android 2.3 GINGERBREAD to Android HTC DESIRE

There's full instruction list on HOW TO INSTALL GINGERBREAD (Android 2.3) onto the HTC DESIRE over at BrightHub.

Some of the important steps are:

1. Download (from MARKET) Rom Manager - by ClockworkMod
   
2. Download the HTC Desire Android 2.3 Gingerbread ROM "update-oxygen-2.0-RC5-signed.zip" Download Oxygen 2.0 Gingerbread ROM for your HTC Desire. Note where you save the file on the phone, or tansfer the file to your phone from the pc and note the location.
   
3. In ROM MANAGER, select the Flash Clockworkmod Recovery option. It will install the recovery image and backup the current ROM on your HTC Desire.
   
4. In ROM MANAGER, select "Install ROM from SD Card" option.
   
   Select the Android 2.3 Gingerbread ROM (ocation previously noted) and click on install it.
   NOTE: Make sure to select the Wipe Data and Cache options before you install it.
   
   
5. Wait whilst ROM MANAGER performs the install.
   
   

   
   

6. In case of any problems with ROM Manager on your Desire,
   just boot your rooted HTC Desire into recovery mode and install the ROM via recovery directly.