I’ve used the May version of OSMC without any problems (using the older echo 1 > /sys/class/amhdmitx/amhdmitx0/output_rgb command).
I’m willing to try and reinstall OSMC, but I don’t have a spare SD card lying around. Is there a way to downgrade without one (e.g. using aptitude, or via network)?
EDIT: Will the instructions in this thread work, using OSMC_TGT_vero2_20170615.img.gz instead of the 2016 version mentioned in the original thread?