I think I might have just turned my iPhone into a useless brick

kirmokin Posts: 4
edited August 2012 in iPhone Forum
My brother sold me his iPhone 4, it was running on version 4.1 and was jailbroken.
After syncing it to my itunes I was unable to open any of the apps linked to his computer, and pretty much every app I tried to download from the appstore said I needed version #.##
I figured I needed to upgrade the software, and googled it.
I stumbled upon this and followed it:
Now I can't even do anything on my iPhone because it says it needs a sim that "came with your iphone"

Is all hope lost or is there anything I can do to actually have some use out of my iPhone?