OK, Unlike my last thread, this one works. Not my method thou, here is the source:
Possible way of injecting games to OFW 4.81 without CFW by affigne
1) Extract game and game update. Merge them EXCEPT FOR THE PARAM.SFO FILE.
2) Change the game's App_Ver and Version values with the ones from the update's PARAM.SFO in your PARAM.SFO. Change the category to "HG (Hard Drive Game)"
3) Add GAME to the end of the game folder (for ex. BLES12345 --> BLES12345GAME)
4) Put the folder in game folder of TrueAncestor Backup Retailer and inject it to your backup.
6) Restore and profit.