[GH-ISSUE #479] [Bug]: Auto-configuration of AMS filament slot via filament assignment falls back to Generic instead of selected filament #298

Closed
opened 2026-05-06 12:28:03 +02:00 by BreizhHardware · 9 comments

Originally created by @pichler583-cell on GitHub (Feb 21, 2026).
Original GitHub issue: https://github.com/maziggy/bambuddy/issues/479

Originally assigned to: @maziggy on GitHub.

Bug Description

The automatic configuration of an AMS slot does not work correctly when assigning a filament via the filament assignment workflow.

When selecting and assigning a specific filament to an AMS slot, the system always falls back to Generic instead of applying the selected filament profile.

However, if the same slot is configured manually using the “Configure” button afterward, the correct filament and profile are applied successfully.

Expected Behavior

The selected filament and its assigned profile should automatically be applied to the AMS slot.

Steps to Reproduce

  1. Go to filament assignment.
  2. Select a specific filament (with a defined profile).
  3. Assign it to an AMS slot.
  4. Check the AMS slot configuration.

Printer Model

P2S

Bambuddy Version

0.2.1b2

Printer Firmware Version

01.01.01.00

Installation Method

Manual (git clone)

Operating System

Docker

Relevant Logs / Support Package


Screenshots

bambuddy-support-20260221-115252.zip

Additional Context

No response

Checklist

  • I have searched existing issues to ensure this bug hasn't already been reported
  • I am using the latest version of Bambuddy
  • My printer is set to LAN Only mode
Originally created by @pichler583-cell on GitHub (Feb 21, 2026). Original GitHub issue: https://github.com/maziggy/bambuddy/issues/479 Originally assigned to: @maziggy on GitHub. ### Bug Description The automatic configuration of an AMS slot does not work correctly when assigning a filament via the filament assignment workflow. When selecting and assigning a specific filament to an AMS slot, the system always falls back to Generic instead of applying the selected filament profile. However, if the same slot is configured manually using the “Configure” button afterward, the correct filament and profile are applied successfully. ### Expected Behavior The selected filament and its assigned profile should automatically be applied to the AMS slot. ### Steps to Reproduce 1. Go to filament assignment. 2. Select a specific filament (with a defined profile). 3. Assign it to an AMS slot. 4. Check the AMS slot configuration. ### Printer Model P2S ### Bambuddy Version 0.2.1b2 ### Printer Firmware Version 01.01.01.00 ### Installation Method Manual (git clone) ### Operating System Docker ### Relevant Logs / Support Package ```shell ``` ### Screenshots [bambuddy-support-20260221-115252.zip](https://github.com/user-attachments/files/25457366/bambuddy-support-20260221-115252.zip) ### Additional Context _No response_ ### Checklist - [x] I have searched existing issues to ensure this bug hasn't already been reported - [x] I am using the latest version of Bambuddy - [x] My printer is set to LAN Only mode
BreizhHardware 2026-05-06 12:28:03 +02:00
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Author
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@maziggy commented on GitHub (Feb 21, 2026):

Thanks for reporting this! I looked through the support package logs but unfortunately the debug logging captured MQTT status polling and cloud API calls — there's no actual spool assignment attempt recorded during that time window. The bug likely occurred before debug logging was enabled.

From the code, I can see why this might happen:

When you assign a spool to an AMS slot via the inventory assignment, the system uses the spool's stored slicer_filament field to determine which filament preset to send to the printer. If that field is empty (which is common for manually created spools), it falls back to a generic filament ID like GFL99 (Generic PLA), GFG99 (Generic PETG), etc.

The manual "Configure" button works because you're explicitly selecting the filament profile in the dropdown, and the frontend sends that specific preset directly.

Could you help me confirm this?

  1. Check the spool you were trying to assign — does it have a "Slicer Filament" / filament preset set, or is that field empty?
  2. If you can reproduce it again, please enable debug logging before performing the assignment, then grab a fresh support package right after. I need to see the actual ams_set_filament_setting MQTT command that gets sent.

If the spool's filament preset field is indeed empty, that would explain the behavior — and I can look into improving the assignment flow to better resolve the correct preset.

Separate note: The logs also show all 7 cloud filament preset lookups (P37d2b68, P1464538, etc.) returning HTTP 400 from the Bambu Cloud API. This doesn't affect slot configuration directly, but it means Bambuddy can't resolve preset names for display. Are you logged into your Bambu Cloud account in Bambuddy's settings or imported your custom slicer profiles under profiles -> local profiles?

<!-- gh-comment-id:3938628369 --> @maziggy commented on GitHub (Feb 21, 2026): Thanks for reporting this! I looked through the support package logs but unfortunately the debug logging captured MQTT status polling and cloud API calls — there's no actual spool assignment attempt recorded during that time window. The bug likely occurred before debug logging was enabled. From the code, I can see why this might happen: When you assign a spool to an AMS slot via the inventory assignment, the system uses the spool's stored slicer_filament field to determine which filament preset to send to the printer. If that field is empty (which is common for manually created spools), it falls back to a generic filament ID like GFL99 (Generic PLA), GFG99 (Generic PETG), etc. The manual "Configure" button works because you're explicitly selecting the filament profile in the dropdown, and the frontend sends that specific preset directly. Could you help me confirm this? 1. Check the spool you were trying to assign — does it have a "Slicer Filament" / filament preset set, or is that field empty? 2. If you can reproduce it again, please enable debug logging before performing the assignment, then grab a fresh support package right after. I need to see the actual ams_set_filament_setting MQTT command that gets sent. If the spool's filament preset field is indeed empty, that would explain the behavior — and I can look into improving the assignment flow to better resolve the correct preset. Separate note: The logs also show all 7 cloud filament preset lookups (P37d2b68, P1464538, etc.) returning HTTP 400 from the Bambu Cloud API. This doesn't affect slot configuration directly, but it means Bambuddy can't resolve preset names for display. Are you logged into your Bambu Cloud account in Bambuddy's settings or imported your custom slicer profiles under profiles -> local profiles?
Author
Owner

@pichler583-cell commented on GitHub (Feb 21, 2026):

The profiles are connected (see screenshot), and the ABS profile is properly linked. I also tested this with different filaments — including an original Bambu ABS filament with the official Bambu ABS preset assigned.

Even in that case, assigning the spool via the inventory assignment still results in Generic being applied to the AMS slot.

So the slicer_filament field should not be empty in these cases.

I’ve now reproduced the issue again with debug logging enabled beforehand.
In the new support package, I manually assigned two filaments:

One Bambu filament

One Sunlu filament

Both should already have had proper presets assigned before the test.

I hope this time the ams_set_filament_setting MQTT command is captured properly in the logs.

Regarding the HTTP 400 errors for the cloud preset lookups:
I am logged into my Bambu Cloud account, and I created the filaments after the cloud connection was already active. So the login state should be valid.

Let me know if you need anything specific extracted from the logs.

Image

bambuddy-support-20260221-123009.zip

Image Image
<!-- gh-comment-id:3938640938 --> @pichler583-cell commented on GitHub (Feb 21, 2026): The profiles are connected (see screenshot), and the ABS profile is properly linked. I also tested this with different filaments — including an original Bambu ABS filament with the official Bambu ABS preset assigned. Even in that case, assigning the spool via the inventory assignment still results in Generic being applied to the AMS slot. So the slicer_filament field should not be empty in these cases. I’ve now reproduced the issue again with debug logging enabled beforehand. In the new support package, I manually assigned two filaments: One Bambu filament One Sunlu filament Both should already have had proper presets assigned before the test. I hope this time the ams_set_filament_setting MQTT command is captured properly in the logs. Regarding the HTTP 400 errors for the cloud preset lookups: I am logged into my Bambu Cloud account, and I created the filaments after the cloud connection was already active. So the login state should be valid. Let me know if you need anything specific extracted from the logs. <img width="509" height="1132" alt="Image" src="https://github.com/user-attachments/assets/4ec34dd2-b50b-4bd3-b982-7fafa15ca4da" /> [bambuddy-support-20260221-123009.zip](https://github.com/user-attachments/files/25457542/bambuddy-support-20260221-123009.zip) <img width="447" height="806" alt="Image" src="https://github.com/user-attachments/assets/4cd423a3-cc53-4216-a2cd-533a05eb169f" /> <img width="1397" height="1226" alt="Image" src="https://github.com/user-attachments/assets/8b614b02-69e0-4d3b-b2b7-15e46c80c245" />
Author
Owner

@maziggy commented on GitHub (Feb 21, 2026):

Inventory says color gray and slot config shows blue. Why is that?

<!-- gh-comment-id:3938646703 --> @maziggy commented on GitHub (Feb 21, 2026): Inventory says color gray and slot config shows blue. Why is that?
Author
Owner

@pichler583-cell commented on GitHub (Feb 21, 2026):

Sorry — attaching two additional screenshots for clarification:

One showing the Blue ABS profile correctly linked

One showing the Sunlu profile assigned

Both profiles are properly set on the spool, but when assigning via inventory, the AMS slot still falls back to Generic.

Let me know if you need anything else.

Image Image
<!-- gh-comment-id:3938650819 --> @pichler583-cell commented on GitHub (Feb 21, 2026): Sorry — attaching two additional screenshots for clarification: One showing the Blue ABS profile correctly linked One showing the Sunlu profile assigned Both profiles are properly set on the spool, but when assigning via inventory, the AMS slot still falls back to Generic. Let me know if you need anything else. <img width="451" height="778" alt="Image" src="https://github.com/user-attachments/assets/4ecaf6b8-2709-4feb-a7d4-5546cf7f6c4e" /> <img width="535" height="1147" alt="Image" src="https://github.com/user-attachments/assets/3e6bf3d5-cff6-49e6-a659-1031b906297b" />
Author
Owner

@maziggy commented on GitHub (Feb 21, 2026):

Now you begin again to mix different topics!

You reported the issue for non Bambu Lab spools and now you are talking about Bambu Lab spools. That's very confusing!

For the Bambu Lab spool please do the following (there's no need to manually configure anything for BL spools!):

  • open config modal for ams slot b2 and click "reset slot" at the bottom
  • hover over AMS slot b2 and trigger slot re-read in the little dotted menu

After that the AMS slot should re-read the RFID tag and the slot is auto-configured.

That's for Bambu Lab spools.

<!-- gh-comment-id:3938657815 --> @maziggy commented on GitHub (Feb 21, 2026): Now you begin again to mix different topics! You reported the issue for non Bambu Lab spools and now you are talking about Bambu Lab spools. That's very confusing! For the Bambu Lab spool please do the following (there's no need to manually configure anything for BL spools!): - open config modal for ams slot b2 and click "reset slot" at the bottom - hover over AMS slot b2 and trigger slot re-read in the little dotted menu After that the AMS slot should re-read the RFID tag and the slot is auto-configured. That's for Bambu Lab spools.
Author
Owner

@pichler583-cell commented on GitHub (Feb 21, 2026):

I only used the Bambu spool to rule out any issue with my custom profile.

So this was specifically to exclude the possibility that the problem is related to a self-created preset. Even with the official Bambu preset assigned, the AMS slot still falls back to Generic when using the inventory assignment.

<!-- gh-comment-id:3938660952 --> @pichler583-cell commented on GitHub (Feb 21, 2026): I only used the Bambu spool to rule out any issue with my custom profile. So this was specifically to exclude the possibility that the problem is related to a self-created preset. Even with the official Bambu preset assigned, the AMS slot still falls back to Generic when using the inventory assignment.
Author
Owner

@maziggy commented on GitHub (Feb 21, 2026):

Why do you assign a bambu lab spool to the inventory? That doesn't makes sense at all.

<!-- gh-comment-id:3938665604 --> @maziggy commented on GitHub (Feb 21, 2026): Why do you assign a bambu lab spool to the inventory? That doesn't makes sense at all.
Author
Owner

@pichler583-cell commented on GitHub (Feb 21, 2026):

It’s not about the Bambu spool.

No matter which filament profile I assign to a spool in the inventory, it is not applied when assigning the spool to the AMS slot.

<!-- gh-comment-id:3938669445 --> @pichler583-cell commented on GitHub (Feb 21, 2026): It’s not about the Bambu spool. No matter which filament profile I assign to a spool in the inventory, it is not applied when assigning the spool to the AMS slot.
Author
Owner

@maziggy commented on GitHub (Feb 21, 2026):

Oh Boy....please. This is the third ticket you crushed. You provide inconsistent debug informations. How shall that work? I alreayd wasted much time for issues, because you provided incorrect details. Sorry, but that's not acceptable.

<!-- gh-comment-id:3938675141 --> @maziggy commented on GitHub (Feb 21, 2026): Oh Boy....please. This is the third ticket you crushed. You provide inconsistent debug informations. How shall that work? I alreayd wasted much time for issues, because you provided incorrect details. Sorry, but that's not acceptable.
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