Klipper runtime warning MCU 'mcu' configured for 180Mhz but running at 270Mhz!

mvingtargt · 2026-07-17T22:57:55Z

Hello All!

I have tried everything that I can think of to get rid of the warning in klipper "Klipper runtime warning MCU 'mcu' configured for 180Mhz but running at 270Mhz!", but the darn thing is still hanging on there. I suspect there is a mismatch between my printer.cfg [mcu] clock settings and what the STM32F446 is actually seeing, but I'm not sure where to verify or adjust that. Heads up, I couldn't get the printer to include my nitehawk.cfg file, so I had to integrate it directly into printer.cfg (I'm going to attach that here at the end along with the klippy.log and system loads. It's going to look funny, so just figured I'd get ahead of that). So far here is what I've tried.

Hardware
- Raspberry Pi 4 Model B (Rev 1.2)
- Nitehawk-SB Rev A (Batch 2403)
- BTT Octopus v1.1 (Chip STM32F446ZET6)
mcu configuration

[mcu]
## Obtain definition by "ls /dev/serial/by-id/*" then unplug to verify
##--------------------------------------------------------------------
serial: /dev/serial/by-id/[REDACTED_SERIAL_ID_1]
restart_method: command
##--------------------------------------------------------------------

[mcu nhk]
## Obtain definition by "ls -l /dev/serial/by-id/" then unplug to verify
##--------------------------------------------------------------------
serial: /dev/serial/by-id/[REDACTED_SERIAL_ID_2]
restart_method: command

Updates:
- I made sure that Klipper and the other Mainsail components were up to date.
- crowsnest v5.0.9-1-gf92045ac
- klipper v0.13.0-707-gf604aeee
- mainsail v2.18.2
- mainsail-config v1.2.1-1-gff3869a6
- moonraker v0.10.0-31-gd5ee1712
- sonar v0.2.0-1-g0d1d7c89
- System OS-Packages
Configuration Adjustments:
- I modified the printer.cfg to include the [mcu nhk] information directly.
- I tried adding "baud: 250000", which I later removed since it didn't work. (see example below)

[mcu nhk]
## Obtain definition by "ls -l /dev/serial/by-id/" then unplug to verify
##--------------------------------------------------------------------
serial: /dev/serial/by-id/[REDACTED_SERIAL_ID_2]
baud: 250000
restart_method: command

Firmware Recompilation:
- I followed the LDO guide for the Nitehawk-SB: selecting Raspberry Pi RP2040 & 16KiB bootloader offset, enabled "extra low-level configuration options", and added the !gpio8 pin to the "GPIO pins to set at micro-controller startup". Clock frequency is not an option in the menu connfig.
- Performed make clean and make cycles to ensure a fresh build of the firmware binary.

Flashing Process:
- I used the manual make flash FLASH_DEVICE=2e8a:0003 command while the Nitehawk-SB board was in BOOTSEL mode.
Verification:
- I verified the connection using ls /dev/serial/by-id/, which confirmed both my main board and the Nitehawk-SB are being detected by the host.
- Ensured that Klipper software on my Raspberry Pi is fully updated so that the host and MCU are running the exact same version.

Many full power cycles and Firmware restarts were made just to try to get the machine to play nice (no dice).

Things I havn't tried:
- Switching the USB port on the Raspberry Pi (seems like a long shot)
- Contacting LDO for support.

Has anyone experienced this and found a solution? I've been through the Voron discord to no avail, and I'll post this there later if you all are stumped as well. What are my options here? Attaching pictures of the make menuconfig, octopus v1.1 board, system load information, as well as my printer.cfg (combined with nitehawk.cfg, and klippy log.