Troubleshooting • Re: Raspberry pi 3B+ is displaying incorrectly on 8.8 inch HDMI MPC8801 monitor

Hey, don’t stress — this is a pretty common headache with those ultra-wide HDMI displays. Your Pi and the MPC8801 just aren’t agreeing on the resolution and rotation settings. The main issue is that hdmi_cvt 1920 480 60 6 0 0 0 isn’t being picked up correctly by the Pi.

Here’s a simpler fix that usually works:
Open your /boot/firmware/config.txt (or /boot/config.txt on older images) and make sure these lines are there, replacing any conflicting ones:

hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 1920 480 60 6 0 0 0
display_rotate=0


Then uncomment or add this line if it’s commented out:

dtoverlay=vc4-kms-v3d


(not the FKMS one — KMS works better with newer Pi OS versions).

Save, reboot, and check again. If the image is still vertical, try changing

display_hdmi_rotate=2


or

display_hdmi_rotate=1


to flip the orientation instead of using ARandR — ARandR often fails on newer Pi OS builds because of how the driver handles screen resizing.

If that still doesn’t help, try running:

xrandr --output HDMI-1 --rotate left


from the desktop terminal (if you’re using GUI mode).

Most of the time, switching to dtoverlay=vc4-kms-v3d and forcing HDMI hotplug fixes this exact 8.8-inch rotation issue. You’re close — just a driver quirk, not a broken setup.

Statistics: Posted by inthorn4458 — Sun Oct 19, 2025 9:07 pm

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