# MCU randomly disconnect **URL:** \ **Category:** General Discussion\ **Created:** [July 22, 2025, 4:59am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321 "2025-07-22T04:59:12Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 22, 2025, 4:59am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/1 "2025-07-22T04:59:12Z")
### Basic Information: ![Screenshot 2025-07-22 192840](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/5/1/510bdfb7138188d359a4fba46834d85fa9eb7ee4.png) Printer Model: Voron2.4 MCU / Printerboard: Octopus 1.1 Host / SBC BTT Pi 1.2 klippy.log [klippy.log](https://klipper.discourse.group/uploads/short-url/bZoFNZ8jjSLOPYtKsGyljdaGqJi.log) (2.7 MB) Full log. 40mb. [klippy.zip](https://klipper.discourse.group/uploads/short-url/1m93carQUgBdRmBq66XKfDxnbcM.zip) (3.2 MB) _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: Printer randomly disconnect. Already tried multiple USB cables. BTT’s, short blue shielded cable for ESP32 flashing, and OEM phone data cable. Use contact cleaner to clean surface contact. BTT Octopus(mcu) use klipper fw and toolhead mcu use katapult. ---
**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:** [July 22, 2025, 5:32am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/2 "2025-07-22T05:32:16Z")
Your log does not seem to contain any relevant shutdown events. What is the error message in the webinterface? Please provide a log showing the issue. ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 22, 2025, 6:46am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/3 "2025-07-22T06:46:34Z")
1. It just show MCU disconnect without any explanation. 2. How do I know which file and which line show error? ---
**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:** [July 22, 2025, 7:35am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/4 "2025-07-22T07:35:42Z")
Reproduce the issue and take a screenshot, please. Also attach the `klippy.log` directly after the event. ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 22, 2025, 12:35pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/5 "2025-07-22T12:35:50Z")
![Screenshot 2025-07-22 192840](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/5/1/510bdfb7138188d359a4fba46834d85fa9eb7ee4.png) The file is too large to upload on this site so… > **[Zippyshare - klippy.log](https://zippyshare.day/KHOk6Wk3SxZTwEp/file)** > > Zippyshare is 100% free unlimited file hosting platform that allows users to upload, store, and share files with other - zippyshare.day. [moonraker.log](https://klipper.discourse.group/uploads/short-url/4E6yI5zrV29V2AzOjZNMni3bgmQ.log) (179.3 KB) ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [July 22, 2025, 1:04pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/6 "2025-07-22T13:04:37Z")
> [@erk](#): > > [Zippyshare — Download — klippy.log](https://zippyshare.day/KHOk6Wk3SxZTwEp/file) Please upload your logs here - not to (another) file server. If the log is too long, you can zip to compress it. ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 22, 2025, 1:22pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/7 "2025-07-22T13:22:55Z")
[klippy.zip](https://klipper.discourse.group/uploads/short-url/1m93carQUgBdRmBq66XKfDxnbcM.zip) (3.2 MB) ---
**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:** [July 22, 2025, 3:52pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/8 "2025-07-22T15:52:20Z")
From the log, it seems that the Klippy-host on your BTT Pi is spontaneously restarting. This, in turn, leads to an MCU shutdown and is the consequence of the error you also see on your screenshot – the MCU needs a reset to clear its error condition. - Make sure you are not doing something to initiate it. - Check system logs on the BTT for traces that might provide a clue. ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 22, 2025, 4:46pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/9 "2025-07-22T16:46:07Z")
It look like this. ```auto biqu@VORON-V2:~$ journalctl -u klipper.service -n 20 Jul 22 03:17:18 VORON-V2 systemd[1]: Started klipper.service - Klipper 3D Printer Firmware SV1. Jul 22 11:59:43 VORON-V2 systemd[1]: klipper.service: Main process exited, code=killed, status=11/SEGV Jul 22 11:59:43 VORON-V2 systemd[1]: klipper.service: Failed with result 'signal'. Jul 22 11:59:43 VORON-V2 systemd[1]: klipper.service: Consumed 34min 28.430s CPU time. Jul 22 11:59:53 VORON-V2 systemd[1]: klipper.service: Scheduled restart job, restart counter is at 1. Jul 22 11:59:53 VORON-V2 systemd[1]: Stopped klipper.service - Klipper 3D Printer Firmware SV1. Jul 22 11:59:53 VORON-V2 systemd[1]: klipper.service: Consumed 34min 28.430s CPU time. Jul 22 11:59:53 VORON-V2 systemd[1]: Started klipper.service - Klipper 3D Printer Firmware SV1. ``` ---
**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:** [July 22, 2025, 6:07pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/10 "2025-07-22T18:07:40Z")
This is, unfortunately, an unfavorable result for multiple reasons: - It appears to be a segmentation fault of the host process. - It does not seem to contain any stack traces → manually scrutinize your logs for more information, e.g. syslog, kern.log (check what is available) etc. - You are using a modified Klipper version, so it is unclear if this is a Klipper inherent problem or caused by the modifications → make sure to use the latest cartographer code and firmware. ---
**Author:** ![hcet14](https://avatars.discourse-cdn.com/v4/letter/h/ecd19e/32.png) [@hcet14](https://klipper.discourse.group/u/hcet14)\ **Post date:** [July 22, 2025, 7:50pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/11 "2025-07-22T19:50:43Z")
That’s a very very huge klippy.log [MCU randomly disconnect - #7 by erk](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/7) 😉 My first impression is, you run a very hot system. ![temp_sineos_2](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/e/e/eef13bfba978bf1efb3dbc58e49bb333d9df3c43.png) MCU-TOOLHEAD: (I guess an EBB) up to almost 90°C! That is amazing. Or I made a mistake! LINUX-HOST: BTT Pi 1.2 up to almost 66°C. That’s very hot. MCU-MAIN: Octopus 1.1 over 50°C. I think, that’s ok. I hope my interpretation is right! Where did you mount your BTT Pi 1.2? Close to the chamber? How do you cool it? You should get rid of that. > [@Sineos](#): > > You are using a modified Klipper version, so it is unclear if this is a Klipper inherent problem or caused by the modifications → make sure to use the latest cartographer code and firmware ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 23, 2025, 1:41am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/12 "2025-07-23T01:41:43Z")
- I will try looking into the system log. - For now I change Niceness of klipper.service to -10. - Cartographer is not in used. I burned it out when I try disassembly the toolhead without power down and now using klicky. ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 23, 2025, 1:49am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/13 "2025-07-23T01:49:34Z")
- I mounted BTT Pi directly to side of the chassis fan ![2B1FA73A-561D-4494-8BD2-21B0FE007023](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/a/7/a748ee179275ce63beab78f5092003ff5177b959.jpeg) - I can’t use other version of klipper. This is the only one that work on BTT Pi. [1](https://www.reddit.com/r/klippers/comments/1lst0bj/aftermarket_firmware_for_btt_picb1/) [2](https://www.reddit.com/r/klippers/comments/1lpuerz/cannot_install_klipperscreen_on_btt_pi/) [3](https://www.reddit.com/r/klippers/comments/1m24efy/good_klipper_board_alternative_thats_not_a/) ---
**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:** [July 23, 2025, 6:03am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/14 "2025-07-23T06:03:00Z")
> [@erk](#): > > I can’t use other version of klipper. This is the only one that work on BTT Pi. [1](https://www.reddit.com/r/klippers/comments/1lst0bj/aftermarket_firmware_for_btt_picb1/) [2](https://www.reddit.com/r/klippers/comments/1lpuerz/cannot_install_klipperscreen_on_btt_pi/) [3](https://www.reddit.com/r/klippers/comments/1m24efy/good_klipper_board_alternative_thats_not_a/) These are very likely problems that could have been solved quite easily. > [@erk](#): > > Cartographer is not in used. This is good, as it takes out the need for modification. I propose the following course of action: 1. **Backup** your Klipper configuration files. 2. Use a new SD card **of good quality** to exclude errors coming from it. 3. Flash either the [Armbian CB1](https://www.armbian.com/bigtreetech-cb1/) **server image** or the latest [BTT image](https://github.com/bigtreetech/CB1/releases) to the card. I **strongly** recommend trying the Armbian one first. 4. Run `sudo apt update && sudo apt full-upgrade`, reboot, and check the board is generally working. 5. Use the latest KIAUH to install everything. Choose `xorg` if asked. 6. **Build and flash new** Klipper firmwares for the board and EBB 7. **Remove** the cartographer from the `printer.cfg`. 8. Put back your configuration files. 9. Reboot and check if everything comes up properly. Hardware-wise make sure that you have oriented your fans such that you secure an airflow in the shown direction: ![grafik](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/4/5/45cc74db34bb6b5a685f24a8aed719635862122c.jpeg) ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 23, 2025, 6:59am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/15 "2025-07-23T06:59:48Z")
armbian problem: After first time setup wizard reboot to the non-root user. Lost access to wireless network entirely. Tried on multiple sd card to no avail. ---
**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:** [July 23, 2025, 8:30am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/16 "2025-07-23T08:30:35Z")
> [@erk](#): > > After first time setup wizard reboot to the non-root user. This is normal for modern Linux distributions, and it is done intentionally. Work with `sudo` or research how to activate direct `root` access (not recommended). > [@erk](#): > > Lost access to wireless network entirely. Tried on multiple sd card to no avail. Try to activate the wireless connection with `sudo armbian-config` ---
**Author:** ![hcet14](https://avatars.discourse-cdn.com/v4/letter/h/ecd19e/32.png) [@hcet14](https://klipper.discourse.group/u/hcet14)\ **Post date:** [July 24, 2025, 7:32pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/17 "2025-07-24T19:32:40Z")
Mmmmh, very hot system. I wonder why your MCU-TOOLHEAD is still working. The temperature is WAY too high. You could turn the BTT Pi 1.2 90° CCW. You got enough space. I think this would improve the cooling. Also don’t place the USB cable above (or under, depends on the perspective) the heatsink. This also reduces the cooling a tiny bit and you are struggling with every degree 😉 ![suggestion](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/e/b/eb9b1ad3f3aa539656149f069f295ef4bff14035.jpeg) ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 25, 2025, 1:07pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/18 "2025-07-25T13:07:23Z")
Update: ```auto 2025-07-25T13:00:44.231357+00:00 VORON-V2 KlipperScreen-start.sh[2145]: 20250725 13:00:44,229 [job_status.py:update_filename] - Updating filename to temperature_tower_ASA_1h3m.gcode 2025-07-25T13:00:44.232365+00:00 VORON-V2 KlipperScreen-start.sh[2145]: 20250725 13:00:44,229 [job_status.py:_update_file_metadata] - Update Metadata. File: temperature_tower_ASA_1h3m.gcode Size: 4023469 2025-07-25T13:01:33.126857+00:00 VORON-V2 systemd[1]: klipper.service: Main process exited, code=killed, status=7/BUS 2025-07-25T13:01:33.127647+00:00 VORON-V2 systemd[1]: klipper.service: Failed with result 'signal'. 2025-07-25T13:01:33.131062+00:00 VORON-V2 systemd[1]: klipper.service: Consumed 19.825s CPU time. 2025-07-25T13:01:33.161679+00:00 VORON-V2 KlipperScreen-start.sh[2145]: 20250725 13:01:33,158 [printer.py:change_state] - Changing state from 'printing' to 'disconnected' ``` I can’t config wireless in armbian-config as it cannot find a single SSID when I run search. Other method like adding a config file also not work. As it is, I can’t get it to stop randomly restart no matter what. I am buying a Pi now. Likely keep btt as a component tester board as it’s too unreliable for real work in its current state. ---
**Author:** ![erk](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/erk/32/19860_2.png) [@erk](https://klipper.discourse.group/u/erk)\ **Post date:** [July 27, 2025, 5:41am UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/19 "2025-07-27T05:41:48Z")
![S__18776067_0](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/e/4/e4da45e9bf4553cce6837ddeb552e98fb1f2b388.jpeg) RPI4 ![S__18776070](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/6/5/653ce9cd38b11aedc7f7db531946eea89c9da602.jpeg) BTT PI No problem now after upgrading to Pi4. I think the problem mainly came from the BTT’s Klipper prebaked OS image, as there are people who got BTT Pi to work well for them. I have a problem installing Armbian or even installing Klipper from scratch with a minimal BTT image and choose to go with prebaked. So this is possibly the only problem with the BTT’s prebaked Klipper image. But enough is enough. I don’t feel safe letting this board handle my machine anymore. A machine with an AC high-voltage heater that could burn my house down. ![S__18776069_0](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/e/b/eb548e22f13f6a261aad557d47459938717237a8.jpeg) TLDR: Don’t trust a jack-of-all-trades hardware company like BTT to do an SBC right. Just buy a computer from a manufacturer who has a good track record of making computers. ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\ **Post date:** [August 26, 2025, 3:42pm UTC](https://klipper.discourse.group/t/mcu-randomly-disconnect/24321/20 "2025-08-26T15:42:01Z")
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