H2C owners, is everything okay with your nozzle switching?

Bambu Lab H2 Series
1

I recently noticed an interesting effect: immediately after turning on the printer, nozzle switching proceeds normally, in three stages:

  1. The feeder’s pinch roller carriage shifts to the “middle position.”
  2. The left nozzle lowers or raises.
  3. The feeder’s pinch roller carriage moves to the far-left or far-right position.

This is the standard algorithm; the switching is smooth and quiet.
However, if you load filament into the left nozzle (whether via the AMS or manually)—even without printing anything and simply unloading the filament immediately—the switching algorithm changes to this:

  1. The left nozzle raises or lowers with a buzzing sound.
  2. The feeder’s pinch roller carriage moves from the right position to the left (or vice versa) in a single motion.

You can resolve this behavior either by rebooting the printer or by reloading filament into the left nozzle. The issue never occurs while filament is loaded in the left nozzle; it only appears after the filament has been removed via the standard menu procedure.

I found a Reddit post containing a video that shows how the switching occurs in this scenario and the sounds it makes: H2C noise when switching between left and right nozzle : r/BambuLabH2C

Can anyone confirm or refute this pattern? I am running the latest firmware (1.02.00.00). I’ve disassembled the mechanical assembly, and there are no issues there. Everything points to a firmware bug, as it is always “fixed” by rebooting the printer. This isn’t a one-off observation; it’s a consistent pattern confirmed by a dozen tests.

@SupportAssistant, should I open a ticket for this issue?

3

I opened a support ticket, described in detail how to reproduce the “defect,” and attached videos showing both normal and abnormal nozzle switching. They replied that they had escalated the ticket to a senior specialist, since the standard support staff apparently couldn’t figure it out. I haven’t received any further response yet.
I posted about this on the forum to ask other H2C owners to try reproducing the issue; if it happens for everyone (on firmware 1.02…), then the problem is definitely with the firmware. That said, I’m already convinced the firmware is the culprit, but some extra confirmation would be useful.

4

Just a clue, a piece of the puzzle…

01.01.05.00 (20260211)

  • Resolved an intermittent mechanical interference issue between the Hotend Latch Actuator and the Hotend Latch during nozzle switch.

Maybe the bug is back in 01.02.00.00 - You could installing the old firmware, and then you’d know right away whether your theory is correct or not. :grin: :+1: