Having recently moved to China, it turns out my iPhone 3GS won't work with SIM cards here. I paid some guy to jailbreak it and unlock it so that it would work on the Chinese networks/SIMs, but that downgraded it to about iOS 4 so none of my must-have apps like pleco dictionary, maps etc work. I've been trying to 'fix' it ever since. Ideally I would end up with a phone that has iOS 6+ and can take calls here, but failing that I'd be happy just to get back to a phone that can't take calls but has all my old apps. I've been using redsn0w_mac_0.9.15b3. I think I upgraded to iOS 6.1.3, but after couldn't activate it. From what I've read I need to downgrade to iOS 6.0, is that correct? Situation currently: switch on iPhone, shows 'configuration' screen, asking for language, then region, then wifi network. On the rare occasion I can connect on the terrible network here, I get basically: 'activating your phone...activation server unavailable.' If I try to connect via iTunes instead I get: 'There is no SIM card installed in the iPhone you are attempting to activate.' If I try to install 6.0 via redsn0w 0.9.15b3, by selecting 'Select IPSW' and pointing it towards iPhone2,1_6.0_10A403_Restore, I get 'That IPSW is not supported by this version of redsn0w' followed by a fingerprint number. I've read lots of posts where people have this problem. Some suggest the file is named incorrectly, but don't say what the name should be. Some suggest trying iPhone3,1_6.0_10A403_Restore, but I tried that and the same error message comes up. Some suggest the download site is at fault, but I tried downloading the IPSW from http://osxdaily.com/2012/09/19/ios-6-ipsw-direct-download-links/ (which I think links to Apple's servers, I'm not sure) and the same error occurs. What do I do? Should I try something other than redsn0w? An earlier version of redsn0w (from where?) Any advice appreciated, getting this phone working again would make things so much easier.