blinkenlightscard formatted in camera, adding LED .FIR and autoexec.bin on a not bootable card.
click to load firmware
get only a single blink along with the loading... screen
led goes off
then screen goes black
http://imgur.com/a/Qo1dBcamera remains on but locked up with no display of any kind not even a single blinkenlight.
waited 5 minutes and pulled the battery.
same result with CF or SD card.
same process with DISP_5D3.FIR and the same autoexec.bin on a 5D3 shows the Magic Lantern Rescue screen