quarterturn
Participant
Post count: 7

Alrighty, I gave up on 720×240 and went with the following in my /boot/config.txt:

# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87
hdmi_cvt=320 240 60 1 0 0 0

This provides 320×240 at 15 KHz.