My EOS R is open to a bit of experimentation!
A1ex at Magic Lantern recently sent along two firmware files for the EOS R which have been successfully tested on the 5D Mark IV and 80D.
Based on the same boot-loader in the Canon 80D, one of the firmware files is supposed to probe the camera in a first attempt to find the address of the LED light as a marker (and more). Once the LED flashes, that gives away the address of the GPIO attached to it and thus the first stage of controlling the rest of the camera can begin – executing more code on the processor can be attempted in the normal way. The file also tries to probe registers that are present on other Canon bodies, with the results being noticeable on the LCD if they do anything on the EOS R.
The first file, “EOSRLOOP.FIR” wasn’t accepted by the EOS R, unlike the other recent Canon DSLR releases and M50.
On this attempt, we assumed the EOS R test was a bust (be sure to read on), with A1ex speculating:
They changed something in the [firmware]file format, possibly also the encryption. Whatever worked on all models from 50D to M50, it no longer works here. The error message is the same as on previous models and that’s encouraging; however, I’m unable to figure it out by brute forcing.
A1ex hadn’t realised I hadn’t yet tried both firmware updates 
The next firmware update “RLEDID14.FIR” was successfully loaded by the boot loader and firmware update program in the EOS R from the Canon firmware update menu. This is big news because it means Magic Lantern code was able to execute on the EOS R as normal.
The probe was able to display a green screen (see video below) – which demonstrates the possibility to change camera registers and execute code on the main processor.
I am not worried about bricking my camera, because it’s already a brick with a 1.8x crop and rolling shutter to make the leaning tower of Pisa look straight. Joking aside, I am just excited to experiment. Let’s see what happens next.
These are the earliest of early days, remember. Canon is not liable if my camera breaks, so I’ll get to use it as a doorstop, or even a sailboat for a guinea pig. It’s weather-sealed, after all.
