Restore using recovery mode. If you've never synced with iTunes or set up Find My iPhone in iCloud, you'll need to use recovery mode to restore your device. This will erase the device and its passcode. 1  Connect your iOS device to your computer and open iTunes.
So if you have a .deb file: 1  You can install it using sudo dpkg -i /path/to/deb/file followed by sudo apt-get install -f. 2  You can install it using apt-get install package_name. 3  Install gdebi and open your .deb file using it (Right-click -> Open with).
Know exactly why I prefer an iThing to others. A deb file is a packaged group of files, like a zip. It does have a special structure to allow running stuff before or after the files are uncompressed and installed. A Deb file is usually used for Debian Linux operating systems, or variations of it like Ubuntu. The iPhone has nothing to do with Linux, besides both being UNIX based, and sharing a lot of open source apps.