My method is different & requires Visionary, Root Explorer, GFree, Terminal Emulator & one other app.
*Newer models root.sh does not work, including permaroot function in Visionary
*NO Engineering Radio is needed
*Fastboot on ADB does not work on newer devices showing (Remote: Not Allowed)
1. Download Visionary & put on your SD Card from PC. (Need to send you the Visionary app) Make sure you have Unknown Sources checked in Applications in Settings. Install Visionary.
2. Open Visionary, Hit the option that mentions R/W & Hit Temproot.
3. Throw GFree_02.zip from PC onto the SD Card, Download Root Explorer from the one other app i'll specify only in PM.
4. Open Root Explorer & hit mount R/W, Go to /SDCard & hold to select move GFree_02.zip over to the following directory /data/local. Hit Paste, Now hold & Extract GFree_02.zip.
5. Install Terminal Emulator from Market. Open it type the following commands:
chmod 777 gfree
6. It will put a Part7backup onto the SD Card if you need to unroot in the future. You will be rooted & SIM Unlocked. Now hit Home, Goto Visionary & select Permaroot w/ R/W checked & it will restart the device. You are rooted & S=OFF Now. You can hit the Volume Down + Power Key & it'll go into bootloader to check to make sure S=OFF. (Use Volume Down/Up to scroll, Power to select) Make sure you have Fast Boot shut off in Applications in Settings before going to into bootloader because bootloader is disabled when Fast Boot is on. To get out of bootloader select fastboot w/ power button & down to reboot & select again w/ power button.
7. You will download ROM Manager. Its time to flash a recovery. Open Rom Manager & you will hit flash recovery. Select 188.8.131.52. After it downloads & flashed you should get a success message. Now you can go here on your computer: http://mirror.teamdouche.net/?device=glacier
& you will download the latest Gingerbread ROM. Also you need Google Apps here: http://android.d3xt3r01.tk/cyanogen/gapps/gapps-gb-20110120-signed.zip
8. Put on SD Card & go back into ROM manager, Hit Reboot into Recovery.
9. (Use Optical Pad for Scroll & Hit to Select, Back button is enabled) Now you will hit wipe data/factory reset, wipe cache partition.
10. Select install zip from sdcard, choose zip from sdcard. Select the ROM first & scroll down to where it says yes w/ the filename & select it & ROM will install. When complete do the same procedure w/ the Google apps file.
11. You can hit back & reboot system now. COMPLETE!
Visionary can be uninstalled but DO NOT remove Superuser.
BTW this phone was fast on stock. If your device was slow I don't understand how. DoubleTwist just doesn't work right i've submitted a bug report.