I have a Japanese Dreamcast and had the same problem.
You should try to use the Action Replay or The Gameshark by booting the game without any codes. It will play import.
My Shenmue 2 PAL is Original GD-Rom . The utopia boot disc is not booting the game either but give it a try you never know.
You will find some of this tools here:
http://www.megagames.com/dc/dc_utils_bootcd.shtml
I don't know if it will work with a CDR backup but it should.
LEX