I've been hammering way at my iPad and I might have found what you looking for, but the only one I found was for 3.41 one but I'm pretty sure it will work for you, let me know if it does or not and I will keep looking for you.
Try this
1. Install
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2. Copy Cod4 USRDIR to dev_hdd0/"whatever your game folder is"/USRDIR
3. Delete DEFAULT_MP.BIN, DEFAULT_SP.BIN, EBOOT.BIN
4. The game can now be launched like a PSN game