To get a DSI (aka Raspberry Pi ribbon) display to work on a Manta M8P (v2.0 in my case), the steps were a little unclear.

I’m using this display by Fysetc, which seems to maybe not really exist. I spent way too long trying to find info on it, but was barking up the wrong tree. If you’ve got it connected but are just getting a white screen on a CM4-like device, this guide is for you.

The product page notes that you need to remove or comment out the following line from /boot/config.txt on your Pi:

dtoverlay=vc4-kms-v3d

This does need to happen, go ahead and do it.

The remainder of the config is actually board-specific. If you were plugging this into a plain-old Raspberry Pi 4, say, running Raspberry Pi OS, you wouldn’t have to do any of this.

The Manta M8P manual says:

The default display interface is HDMI. The DSI interface of the MANTA M8P is DSI1. To use it, download the DSI1 driver[…]¹

After downloading this driver and restarting, the screen on the DSI interface can be displayed normally. If you want to use the HDMI interface, delete the downloaded /boot/dt-blob.bin driver and restart, then HDMI can output normal

It’s not entirely right, but led me down the correct path. With that tidbit of info, I found this official doc from Raspbery Pi, discussing how to get DSI displays working on compute module boards (which the M8P is, at its core).

It offers a command we can run:

sudo wget https://datasheets.raspberrypi.com/cmio/dt-blob-disp1-only.bin -O /boot/firmware/dt-blob.bin
sudo reboot

Upon doing that, the display was immediately picked up by X11 and thus by KlipperScreen and started working.