Yep, that's possible. I've not looked into it in detail but basically I think it would require decrypting, patching and re-encrypting of the ROM image as its read into SRAM, which should be fine.
I started to get some PIC code running last night. I have a simple PIC and SD card breadboarded out, so I'll get all the SD card filesystem stuff working first then go from there.
Yeah, i was also thinking about this theory, a cheat cart for the lynx might be possible by,
1 a os program were you put in code sothat once you hit enter,it should command a microcontroller to encrypt,manipulate and te.encrypt the rom on let's say a 4MB sram,then it must sent that manipulated rom to another 512KB sram to loading into the lynx,during that loading process it should isolate the lynx internal ram for a hardreset effect in order to start your manipulated game,this way there should be no need to manualy manipulate your game,and the lynx only needs to communicate with the 512 KB rom ,not with the actual game cart,but if you think it sounds impossible?? A lynx emulator for the xbox allows you to put in cheat codes into your lynx games.
So i believe in this proof of concept but let there should be a cheat cartride invented for the lynx to proof this theory.
Sure,this methode will be totally different then other cheat cartrides for other systems,but if it will work, why not,