i have a fully functional jailbroken and unlocked 3G with 3.1.2/05.11.07 (with pwnage/mac). it went off without a hitch the first time, so i've never had to tinker with the phone.

problem is over the years the UI has become so sluggish it is practically unusable.

what is the procedure for rolling back the phone to factory settings and re-jailbreaking/unlocking? would i/could i use pwnage/blacksnow or pwnage/ultrasnow? is one easier/less risky than the other?

sorry i don't know what the proper terms are...so, it makes it hard to do a search. hopefully i've explained it well enough for someone to point me to a tutorial or some more reading.

thanks in advance.

-d

As you have a 3G, this is relatively simple.

iClarified - iPhone - How to Jailbreak Your iPhone 3G on OS 3.1.2, 3.1.3 Using RedSn0w (Windows)
or mac
iClarified - iPhone - How to Jailbreak Your iPhone 3G on OS 3.1.2 or 3.1.3 Using RedSn0w (Mac)
Step 2 should NOT be skipped, you should shift-click (option-click on mac) restore to 3.1.2 again.

Set iPhone up as new. Do not restore from iTunes backup.

iClarified - iPhone - How to Unlock the iPhone 4, 3GS, 3G Using UltraSn0w

thanks for the links.

so, just to be clear; you are saying to follow the two tutorials in order:
first jailbreak using redsnow.
then rejailbreak using redsnow.
then unlock using ultrasnow.

correct?

No.. if you have a windows computer - use the tutorial for redsn0w jailbreak on windows.

If you have a mac - (I would personally use pwnagetool) use the second tutorial for redsn0w jailbreak on mac.

ultrasn0w is installed on your iPhone via Cydia - so it doesn't matter whether you own a mac or windows machine for that step