No video over HDMI/CEC on cold boot

I’ve installed OSMC on my Raspi 3 and can control it via my LG TV’s remote when it is plugged into the power strip when the TV is already on. However, if the Raspi is already plugged in before the power strip is switched on (from being off all night), both devices turn on simultaneously. In this case, however, the TV is set to its internal DVB-S tuner and shows the channel it was set to before being turned off. Switching over to HDMI 1 (ARC) does not show any OSMC or Raspi boot screen but simply a black screen reading ‘no signal’, also when given ample time to boot properly. I’ve switched from OSMC to LibreELEC but to no avail, same symptom.

Curiously enough, the sooner I switch from TV to Raspi during boot, I occasionally do see the RASPI being connected with SIMPLINK (LG’s version of CEC) but on HDMI 2 instead of HDMI1 where it’s actually plugged in. So when I switch from satellite to HDMI1 (which shows no SIMPLINK) I get no signal as well as when switching to HDMI2.

I logged in via SSH to check Config.txt which has the line hdmi_ignore_cec_init=1 but no hdmi_force_hotplug=1 which according to Google might help. Unfortunately I cannot write to the file, not even from the GUI’s ‘My OSMC’. Any suggestions?