Today I had a big scare. I was trying to get all the constants of the buttons and my camera blocked. Moments later I realized that it was not possible to navigate the menus of the canon. Only the icons appeared, but the items were not presented. After a few tries, remove card, remove battery, put battery, remove the lens, place the lens, changes ... so, disconnect, connect, etc, etc ... I was scared but I can resurrect my camera. After a few attempts, I managed to solve the problem because I was able to open the 'My Menu' ... (Mode C1 + Menu + SET) ... this sequence showed me the items of 'My Menu' and I registered the function that cleans the camera settigns, and I enabled this custom menu. After I accept the changes, the camera is working again normally. It seemed a miracle!!!! Huufff
I have not given up yet, I'll start having more careful ... I'll analyze the firmware to obtain the constants of a safer way. I think the code that writes the LCD acceded to an invalid memory area. I still have problems with the VRAM. Solving this problem is now a top priority.