Problem
After installing new servers using the UCS 5.2.3 ISO image on Fujitsu TX1330 M5/M6 systems, the local VGA console as well as the remote console via iRMC are unusable.
The screen freezes early during boot and only shows a systemd-udevd message. No MOTD or login prompt appears.
Access to the system via SSH works without any issues. However, console access is essential during physical installation and maintenance tasks.
Switching between virtual consoles using Alt+F1 … Alt+Fx or Ctrl+Alt+Fx is not possible.
The output of /proc/consoles shows that the console is technically assigned:
tty0 -WU (EC p ) 4:1
ttyS0 -W- (E p a) 4:64
Despite this, no output is visible on the screen.
The issue does not occur with Univention Corporate Server 5.0-10, where console access works as expected.
Root Cause
UCS 5.2.3 is based on a newer Linux kernel compared to UCS 5.0.
Although the system correctly assigns tty0 as the primary console (indicated by the C flag in /proc/consoles), the display freezes once the kernel hands over control to the graphics driver.
This strongly indicates a conflict with Kernel Mode Setting (KMS).
The graphics driver included in the newer kernel does not work correctly with the graphics hardware of the Fujitsu TX1330 M5/M6, causing the console output to stop at the point where the driver takes over.
Solution
To resolve the issue, configure the kernel to use a basic, stable graphics mode instead of switching to the hardware-specific graphics driver.
This can be achieved by disabling Kernel Mode Setting using the nomodeset kernel parameter.
Add the parameter to the GRUB configuration via Univention Configuration Registry (UCR):
ucr set grub/append='console=tty0 console=ttyS0,115200n8 net.ifnames=0 nomodeset'
After applying this setting via UCR, GRUB gets updated, and you can now reboot the system.
The local VGA console and the iRMC remote console should display the login prompt correctly again.