After a few months of my jb'd/unlocked 3GS rebooting on its own accord, it finally bricked (for lack of a better term) on me. I got out of it by updating in iTunes but lost my jb/unlock. I don't need to unlock but I'd like my jailbreak back. So, I'm just looking for confirmation here...

iPhone 3GS
Version 4.2.1
BB 05.15.04
Old Bootrom (31st week of 2009)

I'm using redsn0w 9.6.rc8 to jb but I haven't any ipsw files (can't remember where I saved them; most likely I did not save any of them). I'm downloading them from here -> http://www.hackint0sh.org/f127/22056.htm

Is there anything else I should consider before going through this? I've never used redsn0w so I'm figuring it out as I go along. Any comments would be appreciated.

For redsn0w itself, it's pretty straightforward, be sure to answer that you are old bootrom when it asks you.

If you're going to use the Dev-Team Blog - Ultra-recycle unlock solution

Then read this: http://www.hackint0sh.org/f204/196391.htm and understand the pwnagetool/custom IPSW/Mac OS X requirements before you decide to use the iPad baseband unlock solution.