Install . This allows your device to install unsigned .ipa files.
Use redsn0w (for iPhone 4/3GS) or Absinthe 2.0 (for iPad 1/iPod Touch 4). These are freely available. Youtube Ipa For Ios 5.1.1
If you boot up an old iPad on iOS 5.1.1 today, you will find that the built-in classic YouTube app throws connection errors, and the App Store version refuse to download. However, you can still watch YouTube on iOS 5.1.1 using specialized .ipa files, jailbreak tweaks, and alternative clients. Why YouTube Stopped Working on iOS 5.1.1 Install
After extensive testing on an iPod Touch 4G (iOS 5.1.1), these are the only reliable versions. Youtube Ipa For Ios 5.1.1
Your device must be jailbroken to install the necessary fixes.