First post, by davidmorom
Hi everyone!
Recently I've been adding some games to my MS-DOS collection, and found a very weird situation with Johnny Bazookatone. This game has some kind of incompatibility with the DOSBox implementation of MSCDEX, and the game only shows a black screen, getting stuck on an infinite loop issuing MSCDEX commands 2F 1510 continously.
This is discussed on this very old topic: Johnny Bazookatone - MSCDEX errors. The proposed solution is to play an audio track before running the game, using the program TRKPLA.EXE.
Although this solution works, I find it very "ugly", so I spent a while debugging and patching to get a better solution. The problematic code is found inside the archive DRIVERS.BIN. I patched this file to prevent the program to get stuck in the infinite loop. As the game runs directly from the CD, the BIN/CUE has to be modified to replace the file. CDmage can be used for replacing the file without altering the rest of the image.
I made a second patch, for anyone interested in running the game on real hardware without CD-ROM unit. The game can be played without CD by copying all the files to the HDD folder C:\JB, replacing DRIVERS.BIN with the patched one, running SETUP.EXE to configure sound and JOHNNY.EXE to run the game.
I share the patches in case there is someone interested. I hope this can help someone to avoid a little headache.
