# Option 'serial' is not valid in section 'mcu'

**URL:** https://klipper.discourse.group/t/option-serial-is-not-valid-in-section-mcu/15181
**Category:** General Discussion
**Created:** [March 24, 2024, 12:38pm UTC](https://klipper.discourse.group/t/option-serial-is-not-valid-in-section-mcu/15181 "2024-03-24T12:38:03Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![iflyos](https://avatars.discourse-cdn.com/v4/letter/i/e56c9b/32.png) [@iflyos](https://klipper.discourse.group/u/iflyos)
#### Post date: [March 24, 2024, 12:38pm UTC](https://klipper.discourse.group/t/option-serial-is-not-valid-in-section-mcu/15181/1 "2024-03-24T12:38:03Z")

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### Basic Information:

Printer Model: Raise3D N1  
 MCU / Printerboard: Octopus Pro V1.0/Raspi 3B  
  
[klippy.log](https://klipper.discourse.group/uploads/short-url/5q1IhsEnmy0Os1sTOsA4yzH1D3b.log) (120.0 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:

…  
 ![image](https://global.discourse-cdn.com/free1/uploads/klipper/original/2X/d/d495b7135f61b1fc7304fb259677b9e379f684f6.png)

I updated Klipper to v0.12.0-131-gd9043345, and flashed to corresponding firmware to my Octopus Pro as well. When I issue the 'ls /dev/serial/by-id/\* command, I get the output seen in the above screenshot, yet when I start the printer I get **Option ‘serial’ is not valid in section ‘mcu’**

This setup was working fine when I was still on v0.11.something releases. I’m sure I am overlooking something simple, but I just can’t figure it out..

Thanks in advance.

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### Author: ![LifeOfBrian](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/lifeofbrian/32/2380_2.png) [@LifeOfBrian](https://klipper.discourse.group/u/LifeOfBrian)
#### Post date: [March 24, 2024, 1:05pm UTC](https://klipper.discourse.group/t/option-serial-is-not-valid-in-section-mcu/15181/2 "2024-03-24T13:05:32Z")

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You either use a `serial` or a `canbus_uuid`.  
For your Octopus you currently set up both:

```auto
[mcu]
serial = /dev/serial/by-id/usb-Klipper_stm32f429xx_22002B001450304738313820-if00
canbus_uuid = af1b05b21db2

```

As this MCU should be connected to the RasPi via USB just use the serial parameter and delete the canbus\_uuid.

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### Author: ![iflyos](https://avatars.discourse-cdn.com/v4/letter/i/e56c9b/32.png) [@iflyos](https://klipper.discourse.group/u/iflyos)
#### Post date: [March 24, 2024, 4:51pm UTC](https://klipper.discourse.group/t/option-serial-is-not-valid-in-section-mcu/15181/3 "2024-03-24T16:51:31Z")

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@LifeOfBrian Thank you…I knew I was overlooking something simple and your response reminded me of exactly what it was.

Long story short, I am actually using CANbus, because I also have an EBB42. I completely skipped over all the CANbus stuff, because out of 3 printers on Klipper, this is the only one I have using CANbus. Anyway, after correcting that, and flashing the EBB42 (just in case) I am back in business.

Thanks!

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### Author: ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)
#### Post date: [May 23, 2024, 4:52pm UTC](https://klipper.discourse.group/t/option-serial-is-not-valid-in-section-mcu/15181/4 "2024-05-23T16:52:26Z")

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