sirghoul@optonline.net wrote:
On Mon, 01 Jun 2009 23:29:14 -0700, "Michael J. Mahon" <mjmahon@aol.com> wrote:sirghoul@optonline.net wrote:I have an original of the program RSVP that I've been trying to convert to .dskFWIW, the DDMOVER program contains a decryption routine at $8CE1 that does a "running" or "chain" EOR to decrypt the code stored at $8AFA to $8BFB. Patching the RTS at $8D26 to BRK and running the code will reveal the decrypted code. -michael<grin> All of which is beyond my skills. I can follow along in an explanation, and perform the part where it says 'copy this to here, make these changes, viola!!'. I've disabled a few boot-up crackscreens by finding the jump to the unpacking code, and the infinite wait-for-a-keypress loop, but RWTS?? mostly Greek to me.
No RWTS required! Just BLOAD DDMOVER and patch $8D26 to $00 (BRK), then 8CE1G. The machine will "break" almost immediately, then you can examine the code (and data) in the region $8AFA..$8BFB and I can guarantee that you will see what it does to signature check the disk. (Of course, that means accessing the disk, so there things may get more technical.) With any luck, you can just patch the entry point to CLC/RTS ($18 $60) and the program will assume that the check was passed, but that's only speculation--I haven't looked at the code myself, either. ;-) -michael ******** Note new website URL ******** NadaNet and AppleCrate II for Apple II parallel computing! Home page: http://home.comcast.net/~mjmahon/ "The wastebasket is our most important design tool--and it's seriously underused."