I'm sure I checked the download page before, that must have been added recently...
I guess I'll give it a try.
Don't! Braiins support got back to me this morning saying there are a handful of variants of the R4 which the FW simply doesn't work on for unknown reasons. There is also no SD card slot so no way to revert to factory. I'm in a pickle with this R4 (glad I only did one machine) until Braiins figures this out.