Sometimes ? Right could be two things. 1st Make sure you have added the content from disc one to HDD in the right place. Show me a pic what you did and where you placed it. 2nd If you have done that right its more than likey a bad burn. What media you using ? what speed you burning at ? what you using to burn your games (burner) Also just to rule out bad burn try and install disc 2 to hdd via microsoft dash. If it gets a error and don't install 100% then its a bad burn.
Disc unsupported means the console can't read the security data of the game, meaning you forgot to patch the game with topology data or you did patch with topology data but you're on lt 2.0, which can't read topology data hints the unsupported error. Did you update abgx360 with the new .ini file? If you didn't then that's your problem, you need to update abgx360 in order to connect it online and receive the topology data when patching the game.
Bro thought you would of run through ABGX first seeing as its Flashed 360. First rule of any game on flashed 360. Also run it throught ABGX twice just to make sure. Anyway happy you got it sorted out Photos: Spoiler Top Man BKJ7
Just go into DVD and under content folder you'll find a folder 000... and inside this the relevant folder which you need to copy to your own hard drive under content/000...