| Author: | Lord Crass (guest: search) |
|---|---|---|
| Date: | Sun, Jun 12th, 2011 @ 23:29 ( . ) |
When documenting the drive-side protection on Star Rank Boxing v2 and Championship Baseball, I only briefly looked at the C64-side of this protection. Deeper inspection reveals it to be a virtual machine protection, like the early EA FAT track loader that's documented on this site. The p-code instruction loader sits in an IRQ handler. The purpose of it is to obfuscate the uploading of code to the drive (M-W/M-E, etc) in order to trigger the protection. Stack tricks up the wazoo. More investigation is needed though to see what else it can do. By looking at the instruction table, there appears to be 20 instructions. If you've ever looked at the copy program parameters for these two titles, you've probably noticed they're a bit...different. Now you know why. The SRB parameter on Maverick actually performs a full crack of the game, using the game's own loader to read everything into memory, then saving it off as a 3 file backup (loader plus 2 data files since the size is > 202 blocks). The Championship Baseball parameter also hijacks the loader and winds up bypassing the whole title screen and intro sequence. Another nice job by Harald. |
--- 0 Users Online --- 0 Recent Unique Posters |