I'm creating a HDMI to TTL daughter board for a LCM.
The LCM in question has a custom resolution (480x640)
Config is set as follows:
hdmi_cvt= 480 640 60 1 0 0 0
When plugging into a monitor directly, before connecting to the daughter board, I see "Input Not Supported" as expected.
I can then remove the HDMI cable from the monitor and connect to the daughter board and see a stable image.
Otherwise, connecting to the daughter board directly and performing a power cycle, the Pi3+ does not reach the desktop. It just continues to cycle through the boot process.
Changing hdmi_force_hotplug does not seem to have any effect.
My question is, may this be related to either the GPU allocated memory or the hot-plug trigger for the HDMI interface?