I want to downgrade my 3GS to iOS 4.1 without jail breaking it. Apple is still signing 4.1 for the 3GS and I have blobs saved from Tiny Umbrella. The 3GS is currently on 5.0.1. I've been putting it in recovery mode, running TSS server from TU, and selecting the 4.1 ipsw using option+restore in iTunes, but every time I get a different error message. Is it even possible to downgrade a non-jailbroken device, with blobs? I cannot find any clear instructions on how to do it anywhere. Thanks!