How to Install Android 2.3 Gingerbread on HTC T-Mobile myTouch 4G
1. First of all, you need to download an Android 2.3 Gingerbread ROM for your HTC myTouch 4G.
Get the Glacier Gingerbread ROM from XDA. It is Android 2.3 Gingerbread based on CM7 for myTouch 4G.
Download Glacier Gingerbread ROM for myTouch 4G
Connect your phone to your PC and transfer this ZIP to your phone's SD card.
Also download all the Google apps for Android using this link. It is needed if you want to install the official Google apps for Android.
Download Google Apps
Copy the Google apps to your phone's SD card too.
2. Now, start Android Market and search for ROM Manager. Install Clockwork Mod ROM Manager on your phone.
Start Clockwork Mod ROM Manager and click on Flash ClockworkMod Recovery to install a recovery image. Also, back up your current ROM.
3. Now go to the ROM Management section and select the Install ROM from SD Card option. Select the GingerTouch ROM from the SD card and install it. Wipe Data and Cache before you install this ROM.
Also, flash Google Apps if you want to install all the default Google Apps on your myTouch 4G.
In a few minutes, your myTouch 4G will be running Android 2.3 Gingerbread.
In case you have any doubts or issues with the ROM, please visit the official XDA thread for this ROM.
ROM Source: XDA