K1 Max Toolhead MCU – Successful flash but app_start fails (timeout on connect)

General Discussion
1

Basic Information:

Printer Model: k1 Max
MCU / Printerboard: Manta m8p 2.0
Host / SBC: CM4 w/32gb emmc
klippy.log

klippy.log (95.7 KB)

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Describe your issue:

Hi all,

I’m working on upgrading my Creality K1 Max with a Manta M8P mainboard, and I’m stuck with the toolhead MCU. I can successfully flash firmware to the toolhead using mcu_util.py, but the bootloader never starts Klipper afterwards.

Hardware details

  • Printer: Creality K1 Max

  • Toolhead board: NOZZLE-C-V13 (GD32F303CBT6)

  • Flashing via: USB → RS232 adapter

  • Mainboard: Manta M8P (STM32H723)

  • Host: CM4 running Mainsail OS

What works

  • Flashing with mcu_util.py succeeds every time. Example log:

    Firmware updated successfully
send app_start request
send app_start request
send app_start request
App start failed after 3 retries

  • Bootloader handshakes, accepts firmware, and reports flash completed.

What fails

  • The MCU never responds after reboot.

  • Klipper log shows:

    mcu 'toolhead': Timeout on connect
mcu 'toolhead': Serial connection closed

  • Full power cycles don’t help.

  • I tried building firmware with:

    • STM32F103 processor

    • Serial (USART1, PA9/PA10), 250000 baud

    • Clock: 8 MHz (also tested 12 MHz)

    • Bootloader offset: 8 KiB and 16 KiB

  • All combinations flash cleanly but still fail app_start.

What I’m asking

  • Has anyone successfully built Klipper for the K1/K1 Max NOZZLE-C-V13 (GD32F303CBT6) toolhead?

  • Which menuconfig settings (offset, crystal, etc.) are confirmed working?

  • Could this board require something non-standard (different offset, USB vs UART build, etc.)?

Attachments

  • Full klippy.log attached.

Thanks in advance for any guidance!…

2

Welcome jbrazy91,

I don’t know the K1 and the GD32F303 MCU. I just did a simple search for “GD32F303” here and found this solved thread https://klipper.discourse.group/t/klipper-on-ender-3-neo-gd32f303.
There is klipper/config/printer-creality-ender3-v2-neo-2022.cfg at master · Klipper3d/klipper · GitHub mentioned. Same MCU but different offset 28 KiB. Since you know how to flash, I would give it a try.
I fear you lost the bootloader on your GD32F303 MCU with all your trys. Keep that in mind!

The K1 is a nice printer with a terrible firmware. I’ll keep my fingers crossed for you! I guess you could be the first one getting a genuine Klipper running on that printer!