I'm so so sorry for posting the same question as everybody else does, but the solutions that were given to them are not working for me. I've been trying to upgrade my iphone 3GS from ios 4.0 (jailbroken) to 5.1.1, since some applications require higher ios. The problem is whenever I tried to restore a pop-up comes up saying that my device isn't eligible for the requested build. I clicked the more information and these steps came out: 1. Update to the latest version of iTunes. 2. Check that your security or firewall software is not interfering with ports 80 or 443, or with the server gs.apple.com. 3. Follow Troubleshooting security software. Often, uninstalling third-party security software will resolve these errors. 4. An entry in your hosts file may be redirecting requests to gs.apple.com. I've done all of those steps correctly and the problem is still there. I've also searched in Google and Youtube and these solutions came out 1. edit the hosts (adding "#" before 18.104.22.168 gs.apple.com) / (deleting the 22.214.171.124 gs.apple.com) / (changing 126.96.36.199 gs.apple.com into #127.0.0.1 gs.apple.com) 2. restarting my imac 3. changing the USB Port 4. creating a custom IPSW 5. using tiny umbrella (unchecking "set host to cydia on exit') - this is the most confusing step for me, as whenever I open tiny umbrella, the box is already unchecked I've done all of those steps TOO!!! and the problem is STILL there. I don't get it, am I the only one that still have this problem even after I did all of the resolutions?? pleaseee HELP me!!!