you can do either but doing as new is the cleanest way.
BE VERY CAREFUL, WATCH WHAT YOUR DOING !!!
When promted if I want to download and update to 5.0.1, I clicked ok
(but the next screen that popped was for 5.1, (not 5.0.1)
I quickly unplugged my JB4s, then clicked cancel on the screen.
SO BE CAREFUL, don't click on 5.0.1 without watching for what pops up in the next window.![]()
use this to download:
http://www.iclarified.com/entry/index.php?enid=750
than either alt-restore or shift-restore in itunes to update with your downloaded ipsw
thats the case anyway, if something makes you restore you'll have to move to 5.1