Hello just stumbled across this and want to know what you have to do to get the levels, downhill jam, school and philly and west side and test level? https://hiddenpalace.org/Tony_Hawk's_Underground_(Aug_15,_2003_prototype)
Thanks for the info!
- To unlock the game, open the disc image in a hex editor and set the value located at 0x14F6420E to 00. Then edit the two references to startup.qb at 0x000DE9D2 and at 0x2DE3E4E7 to something else. Note that both replaced references still have to be consistent.
- To unlock some of the additional levels like "West Side" and the test level, set the values at addresses 0x2DF1D592 and 0x2DF1D5A3 both to 01.