Can't seem to get OrangePi 5 to work with HAMTYSAN 10.1'' Raspberry Pi Screen Touchscreen Monitor 1024×600

[Frankenmint]

I've tried adding in the following settings to my /config/firmware/ubuntuEnv.txt:

hdmi_force_hotplug=1 hdmi_cvt=1024 600 60 3 0 0 0 hdmi_group=2 hdmi_mode=87 disable_overscan=1

But whenever I plug in the monitor I just get a 'signal not found' prompt on the screen itself. I have confirmed that the monitor works fine when I plug other hdmi devices into it like my desktop machine and a video camera - just not on this orange pi 5 I'm trying to use with it.