# Mcu Unable to connect and Printer is not ready, klippy host is attempting to connect, Ender 3 S1 Pro, Follow up to previous post

**URL:** <https://klipper.discourse.group/t/mcu-unable-to-connect-and-printer-is-not-ready-klippy-host-is-attempting-to-connect-ender-3-s1-pro-follow-up-to-previous-post/25526>\
**Category:** General Discussion\
**Created:** [January 19, 2026, 2:32am UTC](https://klipper.discourse.group/t/mcu-unable-to-connect-and-printer-is-not-ready-klippy-host-is-attempting-to-connect-ender-3-s1-pro-follow-up-to-previous-post/25526 "2026-01-19T02:32:52Z")\
**Posts on this page:** 1\
**Showing post:** 14

<div class="post-metadata">

**Author:** ![hcet14](https://avatars.discourse-cdn.com/v4/letter/h/ecd19e/32.png) [@hcet14](https://klipper.discourse.group/u/hcet14)\
**Post date:** [January 22, 2026, 8:53pm UTC](https://klipper.discourse.group/t/mcu-unable-to-connect-and-printer-is-not-ready-klippy-host-is-attempting-to-connect-ender-3-s1-pro-follow-up-to-previous-post/25526/14 "2026-01-22T20:53:17Z")

</div>

Ok, but I warn you. I’m not that good with Linux.

I have an idea, what might go wrong. But I’m not sure!

Any help analyzing the “dmesg.txt” from strikingtwice is very appreciated!

dmesg.txt

- Line 450: [Jan21 23:37] WARN::dwc\_otg\_hcd\_urb\_dequeue:639: Timed out waiting for FSM NP transfer to complete on 3

> [@CanBus Failing during printing "Got error -1 in can write"](https://klipper.discourse.group/t/canbus-failing-during-printing-got-error-1-in-can-write/8051/2):
>
> Just started seeing these errors in my syslog, Apr 25 11:34:56 octoprint.local kernel: Apr 25 11:34:56 octoprint.local kernel: WARN::dwc\_otg\_hcd\_urb\_dequeue:639: Timed out waiting for FSM NP transfer to complete on 3 Apr 25 11:34:56 octoprint.local kernel: Apr 25 11:34:56 octoprint.local kernel: WARN::dwc\_otg\_hcd\_urb\_dequeue:639: Timed out waiting for FSM NP transfer to complete on 4 Apr 25 11:34:56 octoprint.local kernel: Apr 25 11:34:56 octoprint.local kernel: WARN::dwc\_otg\_hcd\_urb\_dequ…

> **[Raspberry PI + Stickminer : dmesg error report - WARN::dwc\_otg\_hcd\_urb\_dequeue..](https://bitcointalk.org/index.php?topic=5500703.0)**
>
> Raspberry PI + Stickminer : dmesg error report - WARN::dwc\_otg\_hcd\_urb\_dequeue..

Sorry I’m also just a www (no AI) searcher.

Any help here is very, very appreciated 😰!

> [@strikingtwice](#):
>
> MCU / Printerboard: Rasp pi 3, USB C into front port  
> Host / SBC Klipper/Mainsail

See also [https://klipper.discourse.group/t/klipper-architecture-ecosystem](https://klipper.discourse.group/t/klipper-architecture-ecosystem).

I don’t think RPi3 has an USB-C port. Do you have a 64bit OS on your RPi?

---

_[View the full topic](https://klipper.discourse.group/t/mcu-unable-to-connect-and-printer-is-not-ready-klippy-host-is-attempting-to-connect-ender-3-s1-pro-follow-up-to-previous-post/25526)._