I. Before You Begin
1. This method gives you temporary root, but you can go to the next procedure immediately after finishing this one to get permanent root and s-off.
2. This will allow you to WiFi tether (if you can find an appropriate WiFi tethering app for the phone).
3. If you are on Android 2.3 or higher, you must downgrade first. Head here to do that then come back to this procedure to continue.
II. Root the G2
1. On your phone, go to Settings > Applications > Development > and make sure USB Debugging is ON (it MUST be ON) and make sure Fastboot is checked OFF (if it exists in your settings, otherwise don’t worry about it).
2.Download Visionary from here (Link updated 09/11/12 )
3. Plug in your phone via USB cable and mount the sd card so we can transfer files to it.
4.Copy the Visionary .apk file to the root of your phone’s memory card (NOT in any folder just on the sd card itself).
5. Then simply open any file manager app on your phone (like Linda File Manager for free from the Market for example) find the visionary apk file in the file manager and click it and follow the prompts to install it.
6. Once installed, open Visionary and check ON Temp Root After Reboot, and check ON System R/W After Root. Then click TempRoot Now and wait for it to finish.
7. Once it is done, you have temp root and can use rooted apps without rebooting, OR continue to the next procedure to gain persistent root access and s-off to load custom ROMs, etc.
III. Gain Persistent Root and S-OFF
1. Head over to our How To: Gain Permanent Root and S-OFF on the T-Mobile MyTouch 4G / HTC Glacier