The method that's been posted around, originally (I think) from Rootzwiki works in principle, but does not give a persistent root, and the procedure needs some fleshing out. This is the method I used to achieve persistent (although reversible) root on the Rev.
1) Get ADB working (I'm using Linux, BTW, so I can't really help with Windows issues). Get into a terminal.
When the command adb devices
produces an output like:
List of devices attached
Then you are in business.
2) On the phone, make sure you have "Internet Connection" selected as your USB connection mode, and USB Debugging selected in Menu -> Applications -> Development (as previously discussed, USB debugging will remain greyed out until Internet Connection is selected).
Grab SU, Rageagainstthecage-arm5.bin and busybox, which are all in a zip file I have attached below.
3)Place all three files in a convenient location for pushing with adb (your /[Path-To-SDK]/platform-tools directory would be a great idea)
4)We need to get our rooting tools onto the phone, so from your terminal, type:
adb push su /data/local/temp
adb push rageagainstthecage-arm5.bin /data/local/temp/rage
adb push busybox /data/local/temp
Now enter adb shell like this:
You will now see a "$" prompt.
Now wait until you get kicked all the way back to your terminal prompt
. If you see the "$", don't do anything, just keep waiting! When it's done you'll be all the way out of ADB, which you will now need to restart.
5) Get back to the adb shell:
Instead of a "$" prompt, you should now see a "#". Congratulations! You're rooted!
Now to make it stick:
6) (This is the part that people were getting stuck on) Now you need to remount your /system directory as read/write, so type:
mount -o remount,rw -t ext3 /dev/mmcblk0p12 /system
Your /system directory is now mounted read/write.
Now to move the tools we pushed earlier into their new homes:
cat /data/local/temp/su > su
cat /data/local/temp/busybox > busybox
chmod 4755 su
chmod 4755 busybox
At this point, you may want to remove the files you put in /data/local/temp: This is just housekeeping, the files won't hurt anything if you leave them there.
When your phone reboots, go to the market and download Superuser.
This worked for me, hopefully it will work for you!