# Klipper on a sovol SV04: MCU unable to connect **URL:** \ **Category:** General Discussion\ **Created:** [March 14, 2024, 7:43pm UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932 "2024-03-14T19:43:49Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![redTitanium](https://avatars.discourse-cdn.com/v4/letter/r/ee7513/32.png) [@redTitanium](https://klipper.discourse.group/u/redTitanium)\ **Post date:** [March 14, 2024, 7:43pm UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932/1 "2024-03-14T19:43:49Z")
### Basic Information: Printer Model: Sovol SV04 MCU / Printerboard: `klippy.log [klippy (3).log](https://klipper.discourse.group/uploads/short-url/kAoZUPBr8FUQPfivTxMaQIHORG5.log) (293.1 KB) _Fill out above information and_ **_in all cases attach your_ `klippy.log` _file_** (use zip to compress it, if too big). _Pasting your_ `printer.cfg` _is **not** needed_ _ **Be sure to check our “Knowledge Base” Category first. Most relevant items, e.g. error messages, are covered there** _ ### Describe your issue: Hi, I’ve been trying to get klipper to work with my sovol SV04 printer for a few days now, but I keep running into the ‘MCU can’t connect’ issue. When I reload mainsail, it says moonraker can’t connect to klipper, and suggests to check to see if klipper and moonraker are running, and if the klippy\_uds\_address in the moonraker.conf file is correct. After doing all the suggested checks, everything seems fine, and I’m not sure where to go from here. I am using the kiauh installation process, and the sovol sv04 specific source files from the following repo: ([GitHub - Bully85/Sovol-SV04-Klipper: All Config for the SV04 to work with Klipper Mirror and Copy (include images and description)](https://github.com/Bully85/Sovol-SV04-Klipper?tab=readme-ov-file#requirements)). … ---
**Author:** ![gaolst](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/gaolst/32/10026_2.png) [@gaolst](https://klipper.discourse.group/u/gaolst)\ **Post date:** [March 14, 2024, 8:06pm UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932/3 "2024-03-14T20:06:34Z")
Your log say that serial device don’t exist. try to follow usual klipper guides about setting up serial device. here is peace of it from here : [Installation - Klipper documentation](https://www.klipper3d.org/Installation.html) > First, it is necessary to determine the serial port connected to the micro-controller. Run the following: > > ```auto > ls /dev/serial/by-id/* > > ``` > > It should report something similar to the following: > > ```auto > /dev/serial/by-id/usb-1a86_USB2.0-Serial-if00-port0 > > ``` > > It’s common for each printer to have its own unique serial port name. This unique name will be used when flashing the micro-controller. It’s possible there may be multiple lines in the above output - if so, choose the line corresponding to the micro-controller (see the [FAQ](https://www.klipper3d.org/FAQ.html#wheres-my-serial-port) for more information). ---
**Author:** ![redTitanium](https://avatars.discourse-cdn.com/v4/letter/r/ee7513/32.png) [@redTitanium](https://klipper.discourse.group/u/redTitanium)\ **Post date:** [March 14, 2024, 8:47pm UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932/4 "2024-03-14T20:47:01Z")
this is the serial address I get from the command: /dev/serial/by-id/usb-1a86\_USB\_Serial-if00-port0 I set the mcu architecture in ‘make menuconfig’ to stm, as that’s what it suggests in the setup I’m using ([github.com/bully-85](http://github.com/bully-85)). when I run the ‘make flash’ command, I get the following: Building hid-flash gcc -c -Wall -std=gnu99 -I . `pkg-config libusb-1.0 --cflags` main.c -o main.o gcc -c -Wall -std=gnu99 -I . `pkg-config libusb-1.0 --cflags` hid-libusb.c -o hid-libusb.o gcc -c -Wall -std=gnu99 -I . `pkg-config libusb-1.0 --cflags` rs232.c -o rs232.o gcc -no-pie main.o hid-libusb.o rs232.o `pkg-config libusb-1.0 --libs` -lrt -lpthread -o hid-flash Flashing out/klipper.bin to /dev/serial/by-id/usb-1a86\_USB\_Serial-if00-port0 Entering bootloader on /dev/serial/by-id/usb-1a86\_USB\_Serial-if00-port0 Device reconnect on /sys/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1/1-1.2/1-1.2:1.0/ttyUSB0 sudo dfu-util -p 1-1.2 -R -a 2 -D out/klipper.bin dfu-util 0.11 Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc. Copyright 2010-2021 Tormod Volden and Stefan Schmidt This program is Free Software and has ABSOLUTELY NO WARRANTY Please report bugs to [http://sourceforge.net/p/dfu-util/tickets/](http://sourceforge.net/p/dfu-util/tickets/) dfu-util: Warning: Invalid DFU suffix signature dfu-util: A valid DFU suffix will be required in a future dfu-util release dfu-util: No DFU capable USB device available Failed to flash to /dev/serial/by-id/usb-1a86\_USB\_Serial-if00-port0: Error running dfu-util If the device is already in bootloader mode it can be flashed with the following command: make flash FLASH\_DEVICE=1eaf:0003 OR make flash FLASH\_DEVICE=1209:beba If attempting to flash via 3.3V serial, then use: make serialflash FLASH\_DEVICE=/dev/serial/by-id/usb-1a86\_USB\_Serial-if00-port0 make: \*\*\* [src/stm32/Makefile:111: flash] Error 255 wrmth@sovol3d:~/klipper $ ls /dev/serial/by-id/\* /dev/serial/by-id/usb-1a86\_USB\_Serial-if00-port0 wrmth@sovol3d:~/klipper $ ---
**Author:** ![gaolst](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/gaolst/32/10026_2.png) [@gaolst](https://klipper.discourse.group/u/gaolst)\ **Post date:** [March 14, 2024, 9:22pm UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932/5 "2024-03-14T21:22:41Z")
Ok, so your flashing process was not over … Did you try what did initial `make flash` suggest ? By definition it should try to use USB connection directly without Serial layer. > [@redTitanium](#): > > If the device is already in bootloader mode it can be flashed with the > following command: > make flash FLASH\_DEVICE=1eaf:0003 > OR > make flash FLASH\_DEVICE=1209:beba ---
**Author:** ![Sineos](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/sineos/32/18_2.png) [@Sineos](https://klipper.discourse.group/u/Sineos)\ **Post date:** [March 15, 2024, 6:31am UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932/6 "2024-03-15T06:31:43Z")
1. From a quick google this printer seems to use a Creality Clone board → These cannot be flashed via `make flash ...` but via copying `firmware.bin` to the SD card 2. There seem to be different variants with STM or GD chips → May be important during `make menuconfig` 3. The Klipper sources in the above project seem modified. If you are having issues, it is recommended to revert to the authors of the modifications ---
**Author:** ![redTitanium](https://avatars.discourse-cdn.com/v4/letter/r/ee7513/32.png) [@redTitanium](https://klipper.discourse.group/u/redTitanium)\ **Post date:** [March 15, 2024, 9:01pm UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932/7 "2024-03-15T21:01:09Z")
It works now! The issue was indeed the flashing method. After manually booting up the firmware onto the printer, it runs smoothly. Thanks for your help gaolst and Sineos! ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\ **Post date:** [April 15, 2024, 7:01am UTC](https://klipper.discourse.group/t/klipper-on-a-sovol-sv04-mcu-unable-to-connect/14932/8 "2024-04-15T07:01:43Z")
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.