Due to the collaborative efforts of a slew of XDA Developers forum members, unforgiven512, scotty2, tmzt, IntuitiveNipple, and grankin01, you are now able to permaroot your lovely myTouch 4G. All you've got to do is follow the directions and BE CAREFUL or you will have a BRICK of pure, hot, technology, just waiting to be tossed in the garbage. And before you get down to the directions and eventually take a hammer to your phone, remember to reminisce on all the good times you had with it.
Take a look at these directions and remember, don't do them unless you know what you're doing and have a good idea of what's at risk.
First make sure you have visionary installed and download these two files:
Here are the md5sums for the modules and hboot: http://www.megaupload.com/?d=CFSHDJS1
1. Fire up your device and run visionary.
2. adb push the two files you downloaded to /data/local on the device:
adb push wpx.ko /data/local and adb push hboot_dhd.nb0 /data/local
3. Open up a terminal on the phone or thru adb shell and gain root (su + enter).
4. Type insmod /data/local/wpx.ko and press enter. You should get an error stating "function not implemented" this is what you want
5. Type dd if=/data/local/hboot_dhd.nb0 of=/dev/block/mmcblk0p18 and hit enter. This command can turn your phone into a very expensive paper weight. Pay attention to what you are typing.
6. If you are on terminal on the device close it out. If you are on adb shell don't worry about closing your session.
7. Run VISIONary again to lock in root.
8. Fire your terminal back up and type sync and hit enter.
9. Wait a couple of minutes and reboot.
10. Run visionary again and reboot again. This will make root stick.
You can now uninstall visionary and enjoy permaroot.
If you want to go into hboot and look it should say s=off!
If you still have problems getting su to work after this uninstall visionary, shutdown, pull battery, and restart. Should work after that. Props to PolishDude for figuring that one out.
[Via XDA Developers Forum]