No hdmi signal to external monitor

Hi all,

I’m trying to connect a Jonsbo D8 8-inch external monitor (1280x800) to my RPI4 running DietPI 9.8.

The monitor is detected properly by my laptop running Fedora Linux. Connecting to the Pi however doesn’t give any signal. I have succesfully used the hdmi output to my amplifier for audio earlier.

The cable i’m currently using is a new cable i’ve ordered from Amazon, it’s micro-hdmi to mini-hdmi. I have no other devices i can test that with other than the RPI4 and Jonsbo D8.

A few config tweaks i have tried:

hdmi_safe=1
config_hdmi_boost=5
hdmi_force_hotplug=1
framebuffer_width=1280
framebuffer_height=800

So far none of the changes have had any effect. I’ve tried hot and cold rebooting the RPI4, re-inserting the hdmi cable after boot, and powering the display on and off.

Does anyone perhaps have any suggestions what else i could try to get a signal on the monitor?