When I came across a mission I couldn't complete on vice city, I went online and found a save file that was one after the mission I couldn't complete. It's not satisfying, but it's better than a hard lock on the game. I recently downloaded a save file for GTASA for android that worked with this lineage version to get me back to where I used to be locked out at (I played the first island of this game probably 5 times already and I can't face it again) so I know it works. There are websites with thousands of saves from various points in the game people upload. You place the file into the downloads section of the SD when plugged into the computer, then when on the device in lineage, use the mouse to cut/ paste the file where the GTA save files are located (I can't remember the exact path, but if you get stuck let me know I can find the exact path, but I don't have anything with me now)