SKR3 V3 Problem 'ls /dev/serial/by-id/`

Basic Information:

Printer Model: Alfawise u20
MCU / Printerboard: SKR3 V3 STM32H723
klippy.log

Description :

Hey everyone,

I’ve got an SKR3 board, and I feel like the millionth person facing issues with it. Here’s the situation:

I followed the standard flashing process with the .bin file, but ran into problems at a key point.

Issue 1:

When I flash the stock firmware-usb.bin from the official GitHub repo, everything goes smoothly.
The file changes to FIRMWARE.cur, and the status LED turns off as expected.

However, when I try flashing Klipper (after renaming it to firmware.bin), the status LED never turns off.
The file gets renamed to : FIRMWARE.cur, but something’s still wrong, and the board doesn’t seem to complete the process.

Issue 2:

Assuming the flashing with the original file worked, I tried moving forward.
I used the command ls /dev/serial/by-id/ to check for the device, but it doesn’t seem to exist.
When I ran ls /dev, there’s no “serial” listed either.

Here’s what I’ve already tried:

  1. Swapped USB cables and confirmed the one I’m using supports data transfer.
  2. Checked the Raspberry Pi’s USB ports with other devices—no issues there; they’re detected with lsusb. The only thing not showing up is the SKR3.
  3. Confirmed that the CAN/USB switch is in the correct (released) position.

At this point, I gave up on USB and tried connecting the SKR3 to the Pi via UART:

  • PA10 > GPIO15
  • PA9 > GPIO14
  • GND > GND

Even with the .bin file from GitHub, it didn’t work.

Does anyone have any suggestions on what to try next? I’d appreciate any help!

Please check what kind of MCU is actually used on your board. It seems that BTT is silently shipping two different variants:

  • STM32H723
  • STM32H743

While both seem “pin compatible”, i.e. the settings in the printer.cfg are the same, they need different handling during make menuconfig.

Hello friend ,
yes that’s correct, mine is 723

Please be very precise with the board you have. There is:


no, as mentioned it’s a BBT SKR 3

additional information :
i tried what was mentioned here Provide support/documentation for STM32H723 variant · Issue #48 · bigtreetech/SKR-3 (github.com)
but with no success

Try following settings:

Copy the firmware.bin to a SD card and reboot the board.

1 Like

Great news—
everything is working now! I’d like to share what I did in case it helps someone else.
To summarize, I found myself stuck in DFU mode for reasons I still don’t understand, which caused the LED status to remain on.
I generated the .bin file and successfully loaded it using the STM32 programmer, as shown in picture “a5.”


Good job.
So the above firmware config worked?

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