CB1 Armbian v3.0.0 fails to start /tmp/klipper_host_mcu

Due to an incorrect kernel configuration, the latest release of the Klipper firmware image for the CB1 cannot access any of the CB1 pins exposed by the device. This is likely caused by a specific option in the kernel build settings, as documented here: https://klipper.discourse.group/t/armbian-kernel-klipper-host-mcu-got-error-1-in-sched-setschedule/1193

Specifically, the kernel config parameter `CONFIG_RT_GROUP_SCHED` should be set to `n` rather than `y`.

The following solution has been theoretically proposed as a workaround, but as it alters the scheduling behavior of the kernel, its unclear to me if it would impact emission of GCODE, or if the MCU is already the bottleneck: https://klipper.discourse.group/t/klipper-mcu-service-fails-to-start/12219

Start with the CB1 Armbian v3.0.0 kernel build settings and verify the CONFIG_RT_GROUP_SCHED value. Reproduce the failure to start /tmp/klipper_host_mcu, then confirm that a rebuilt image can access the CB1 pins without affecting GCODE emission or MCU scheduling behavior.

Written by the indexing model from the issue text.