Ubuntu 24.04 - Kernel 6.8

[kramerbenjamin]

rpi update does not work with the new kernel 6.8 on ubuntu 24.04:
uname -r
6.8.0-1004-raspi

sudo rpi-update
You appear to be using a custom kernel file (kernel=vmlinuz in config.txt).
Skipping installation of new kernel, as bundled dtb files may be incompatible with your kernel.
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
*** Performing self-update
*** Relaunching after update
You appear to be using a custom kernel file (kernel=vmlinuz in config.txt).
Skipping installation of new kernel, as bundled dtb files may be incompatible with your kernel.
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
FW_REV:42312de156405e637a0a171d0cd58b1b2980df11
BOOTLOADER_REV:2bfd7cb74e6bc16559e040d0f5d788a4411819e4
*** Your firmware is already up to date (delete /boot/firmware/.firmware_revision and /boot/firmware/.bootloader_revision to force an update anyway)

Best regards