I tried to post but couldn't but basically I found a guide: psjailbreak.co.cc/play-modern-warfare-2-mw2-backups-online-offline
Play Modern Warfare 2 (MW2) Backups Online + Offline
ZuBiiKz on PSX-Scene has found a way to play MW2 backups online, and additional instructions for Spec Ops/Campaign all on 3.55 CFW.
This has been made and tested by me. 100% Works. 3.55 Only
Put your MW2 USRDIR to dev_hdd0/MW2_GAME/USRDIR (Make a the MW2_GAME Folder in the dev_hhd0)
1. Download both PKGs 1.00 & 1.11 Patch
2. Put it in a USB & Plug it in the PS3
3. Install 1.00 first and then launch and you should get a update 1.11….press yes and wait until its finished downloading and installing.
4. You should notice the PKG that you installed has disappeared then install 1.11 PKG and then launch
5. Go and Pwn some noobs
6. (if you get a black screen, you have done something wrong)
Now for those of you that want to play solo ( special-ops and campaign ) like me try the following it works 100% !:
1) Download the PKG SOLO or Multi ( but multi is already explained thanks to the guy who started this topic !)
2) Install PKG ( copy SOLO or Multi pkg to your usb and insert in PS3 and install the pakage)
3) Remove default.self , default_mp.self , and the original eboot.bin from the downloaded game USRDIR !!! very important !
4) Use your Backup Manager ( mine was mm 01.13.01) to copy the modified USRDIR folder to your ps3 /hdd0/MW2_GAME
5) If MW2_GAME does not exists, just creat MW2_GAME folder with CAPS
6) After copy, go back to xmb and click on the modern warfare 2 icon
7) Play the game !
*8) You can switch from solo to multi and back by just reinstalling the corresponding pkg, with this method you can play both