You can't install packages without Jailbreak.
Originally posted by another user
If you need to bypass MW3 1.21 Update:
1. Delete Mw3 1.22 Update.
2. Download Mw3 1.22 Update.
3. Wait till its on 4/4 and let it go to 20% then just cancle it.
4. Start up patch blocker on you pc.
5. Once it opens put start blocking.
6. On your ps3 go to Settings/Network Settings/Internet Connection Settings
7. Put Custom/Wired or Wireless What Ever You Have It On Then Just Keep Going To The Right Till You Find Proxy Server.
8. Select Use Then Put The IP That Patch Blocker Gave You, Put The Port As 8080.
9. Then Just Keep Going To The Right And Save It. ***Dont Test It Just Save And Exit***
10. Then Just Sign In And Find A Mw3 XP Lobby ^_^