Just plug it to itunes and restore it.
Stay away from "erase all content and settings"
OK, I guess some back story might make sense here. In the event that I want to sell my phone and keep the same FW and BB on it, but still wipe out all of my data that's on the phone, I'm assuming that hitting the Reset All Settings will do this. But using the Erase All Content and Settings route, it will wipe everything out on the phone including the FW & BB. Is this a correct assumption or is there some better alternative to keeping the FW/BB the same while getting rid of all my data on the phone? Thanks.
Reset all settings will not delete or wipe anything off your phone. It will just put some settings back to defaults but all your stuff will still be there.
What model iphone you have and do you have shsh's saved so you can restore/downgrade to anything but the latest 4.2.1?
I see. I have IP4 on 4.1 w/1.59BB. Managed to keep the BB when updating from 4.0.1. Have shsh's on file for 4.0.1, 4.0.2, 4.1 and 4.2b3? not sure what the last one is for. This isn't for the immediate future or anything so I'm not planning on doing this any time soon. I was just curious that when the time came, what was the best way to keep the FW/BB on my phone and still delete all my stuff. I'm guessing I'd have to manually delete everything on the phone in order to do so.
Oh good, with those SHSH's then you're fine.
You can donwload the official 4.1 ipsw and restore back to that by running Tinyumbrella while also maintaining your unlockable baseband.