BIGTREETECH SKR 2 w/ STM32F429

Only Partial support

This board currently cannot be flashed automatically through USB, that means all firmware updates have to be done by physically moving an sd card from and to the board for now. RatOS compiles the firmware binary for you each time klipper is updated (while the SKR 2 is connected), you can find the most recent firmware in the Mainsail Machine page under the firmware_binaries folder). Automatic flashing may be possible in the future if SDIO support is implemented in klipper. See this thread: https://github.com/Klipper3d/klipper/pull/4881#issuecomment-962596510 for more info.

Wiring

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if you use the Ratrig endstop switches and cables, do not blindly plug them in to your SKR 2 as doing this will short the board's 5V power rail.

You will probably have to swap the outer two wires (red and white) on the board end of the cable but double check to make sure your cables match the wiring diagram.

Jumpers

A green square with triangles inside is where you would place a jumper, remove all jumpers on the board that are not marked by this symbol.

Firmware installation

Use a proper cable

Make sure your board is connected to the Pi via the provided USB cable (USB-B on the SKR 2 429, USB-A on the Pi).

Download the firmware-btt-skr-2-429.bin from the firmware_binaries folder found on the Machine page of Mainsail, copy it onto the SD card that goes into your control board and call it firmware.bin, then insert the SD card in to the control board. Here are the steps in chronological order:

1. Navigate to http://RatOS.local/
2. Open Machine page
3. Open firmware_binaries folder
4. Download firmware-btt-skr-2-429.bin
5. Format the sd card for your board to FAT16 (sometimes just called FAT), or FAT32 with a clustersize of 8kb or 4kb.
6. Copy firmware-btt-skr-2-429.bin onto the sd card for your board
7. Rename firmware-btt-skr-2-429.bin to firmware.bin. Please be wary of file extensions! If the file doesn't already show .bin, don't add it!
8. Safely eject the SD card through your operating system.
9. Physically take out the sd card and insert it into your control board.
10. Power cycle your printer or control board. Remember to shut the pi down properly before you cut power to your Pi (you can do that through Mainsail using the dropdown menu in the top right corner).
11. Verify that the firmware has been flashed.

tip

If you don't know how to make Windows Explorer show file extensions, see this article on HowToGeek

tip

You can verify if the board flashed correctly by checking if the firmware.bin file has been changed to firmware.CUR on the SD card. If you have trouble flashing the motherboard, start unplugging your wires beginning with the endstops, sometimes faulty wiring can cause the board to not boot properly.

If you're going through initial setup please continue in the installation guide

Manual firmware upgrade

Sometimes klipper makes changes to the microcontroller code and thus your MCU need to be reflashed with new firmware. If you see an error like this:

And the host version number is larger than the mcu version number, you need to flash your control board. If the host version is lower than the MCU number, you need to update klipper on your pi. RatOS compiles the firmware binary for you each time klipper is updated (while the SKR 2 is connected), you can find the most recent firmware in the Mainsail Machine page under the firmware_binaries folder)

info

RatOS automatically compiles new firmware for your board when klipper is updated and places it in the firmware_binaries folder, you can download the binary from here and flash via SD card manually. Follow the process described above.