iPhone Iphone 3gs upgrade (please Help!)


macrumors newbie
Original poster
Aug 29, 2012
I'm currently running 4.3.1(8g4) on an iphone 3gs and I want to downgrade my baseband (from 06.15.00 to lower) and I also want to upgrade my firmware to 5.1.1. But this is my first time so I really need help on how, what is needed for these two things? ( if there are steps by steps or instructions with pictures or video would be really helpful) and my 3gs is made on the 13th week of 2011?. (xx113xxxxxx:confused:)

And will I lose all my apps? settings?
Thank You,