Put it into %USERPROFILE%\Documents\Rockstar Games\GTA IV\savegames
(download gtaiv_patch_1040.zip), open GTAIV_MAINTENANCE_UPDATE_1040_EFIGS.exe with 7-zip (do not run or double click the patch exe but run 7-zip and use menu to open the patch exe as you would open an archive file), go to $0 subfolder, unpack all to GTA IV folder. Obtain 1.0.4.0 patch GTAIV_MAINTENANCE_UPDATE_1040_EFIGS.exe.IV Complete Edition Radio Downgrader (RGL/Steam) old IVCEDOWNGRADE.rar ~637 mb - note that you need old downgrader, the newest version at will not do for 1.0.x.0 downgrade (it will freeze after Concrete Jungle mission) as it has pc\audio\config files that only work with 1.2.0.x.
Original music sets for radio" (has bundled old radio downgrader),
Running with XlivelessAddon (recommended) 1ĭisclaimer: This method is for advanced PC users and although it was extensively tested and works for me and many other users I do not take responsibility if your downgraded game does not start.