- Update to an older firmware isn't working, because Apple is no longer handing out SHSHs for the device/firmware combination.
- Or a timeout checking Apple server - retry later.
- This error also happens if you try to Update with a local TSS server (TinyUmbrella tool) and probably also when connecting to Cydia Server. Use Restore instead.
- Error 3002 represents no update ramdisk when pressing Shift+Check for updates.
- No internet connection during the firmware restore.
- iTunes can't connect to gs.apple.com. Maybe Port 80 and Port 443 is blocked. Open it on your router.
- Bad hosts file. The SHSH request couldn't be completed. No connection to the Apple Server, Open your host file and remove any lines with gs.apple.com."