P1S + AMS (Gen 1) No Longer Allows Filament Type Changes

Bambu Lab P Series Troubleshooting
1

P1S + AMS (Gen 1) No Longer Allows Filament Type Changes / AMS Not Re-Scanning Slots

I’m trying to determine whether this is a bug, a firmware issue, or a configuration problem after recent software updates.

Hardware:

  • Bambu Lab P1S

  • Original AMS (4-slot AMS, not AMS 2)

  • No firmware updates available for either the printer or AMS

Recent Changes:

  • Updated Bambu Studio to the latest version

  • Updated Bambu Handy to the latest version

  • Printer and AMS both report that firmware is up to date

The Problem:

Prior to these updates, I could easily change filament assignments in the AMS. For example, if I removed a spool of Bambu PETG Transparent and replaced it with a spool of Generic Red PLA, I could manually update the AMS slot to reflect the new filament type and color.

Now I cannot change filament assignments anywhere:

  • Bambu Handy: no edit option available

  • Bambu Studio: no edit option available

  • P1S touchscreen: no edit option available

One specific example:

A slot previously contained Bambu PETG Transparent. I removed that spool and installed Generic Red PLA. The AMS still thinks the slot contains the previous filament and I cannot find any way to change it to Generic PLA.

Additional Observation:

After a power cycle, the AMS no longer appears to perform its normal startup behavior.

Previously, when powering on the printer, the AMS would appear to scan/check each slot during initialization. I no longer observe this behavior.

I have already tried:

  • Power cycling the printer

  • Power cycling the AMS

  • Updating Bambu Handy

  • Updating Bambu Studio

  • Confirming that printer and AMS firmware are current

Despite this, the AMS continues to retain the old filament assignment and provides no obvious way to edit it.

Questions:

  1. Has the ability to manually edit AMS filament assignments been moved somewhere in recent versions of Handy or Studio?

  2. Is there a way to force the AMS to re-scan all slots and forget previous filament assignments?

  3. Has anyone experienced an AMS that still shows old filament data but no longer performs the normal startup slot detection process?

  4. Is there a way to reset AMS filament metadata without factory resetting the printer?

Any guidance would be appreciated. I’m trying to determine whether this is a software/UI change, a firmware bug, or a communication issue between the P1S and AMS.