[RPi 4B] No 4K resolution after upgrade to v9.10 [SOLVED]

Troubleshooting
1

I have searched the existing open and closed issues

Required Information

  • DietPi version | cat /boot/dietpi/.version

G_DIETPI_VERSION_CORE=9
G_DIETPI_VERSION_SUB=10
G_DIETPI_VERSION_RC=0
G_GITBRANCH=‘beta’
G_GITOWNER=‘MichaIng’

  • Distro version | echo $G_DISTRO_NAME $G_RASPBIAN

bookworm 0

  • Kernel version | uname --all

Linux DietPi 6.6.74+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.6.74-1+rpt1 (2025-01-27) aarch64 GNU/Linux

  • Architecture | dpkg --print-architecture

arm64

  • SBC model | echo $G_HW_MODEL_NAME or (EG: RPi3)

RPi 4 Model B (aarch64)

Additional Information

Hello,

I just did upgrade from v9.9 to v9.10 on a RPi 4B (8GB) and successfully switched to the new kernel. I had to manually downgrade libsdl2-dev and libsdl2-2.0-0 during the process when the script halted, due to a dependency issue with the installed version of the latter.

I have dual 4K displays attached, which did output 4K (30p if I recall correctly) before but after the upgrade to version 9.10 with its new kernel, the only option I get is 1920 x 1080. Furthermore, dietpi-display does not work due to “No DRM device has been found” message on the vc4-kms-v3d-pi4 module.

RPi4B_v9-10
RPi4B_v9-10925×1144 80.7 KB

  • ls -l /dev/dri

ls: cannot access ‘/dev/dri’: No such file or directory

Any clue what might have happened and how to restore 4K resolution (possibly with 60p on one screen)?

Thank you!

2

As far as I know the available resolutions are hardcoded into the script and there is no 4K resolution provided by dietpi-config:
https://github.com/MichaIng/DietPi/blob/ddd48297f3b87c1d4f35c5f1e905de3a9ba9f21d/dietpi/dietpi-config#L621

So I guess you set the resoultion manually. Dietpi would set it in /coot/config.txt so we do the same here:
You need to set hdmi_enable_4kp60=1 in your /boot/config.txt (which you probably already did in the past. If not, do it and reboot) and also add hdmi_mode and hdmi_group to set the resolution.

You would need to add the following:

hdmi_enable_4kp60=1

hdmi_force_hotplug:0=1
hdmi_force_hotplug:1=1

hdmi_group:0=1
hdmi_mode:0=97     

hdmi_group:1=1    
hdmi_mode:1=97
2 Likes
3

Thanks a lot for the quick reply! I did add hdmi_enable_4kp60=1 earlier but this alone resulted in a black screen.

The solution was to add the other hdmi_mode and hdmi_group values as you suggested, as well!

1 Like
4

Reading the forum I added video=1920x1080@60e onto consoleargs in boot/dietpiEnv.txt and it boots up in 1080 and I can now select it from the desktop. So maybe if you do the same you will have the same result.

Before, xrandr did not show 1080 but after the parm was added it does.

5

Don’t mix the SBCs. The topic above was about Pi4.

This file didn’t exist on Raspberry SBC

6

Sorry, I didnt know each flavor of Dietpi was so different.

I wondered as there is no boot/config.txt for odroid c4 but a boot kernel parm should be the same no matter what file you have to put it in :wink:

7

this depends on the device family. You can’t place RPi config into other nonRPi device.