[BFW-5772] [BUG] Prusa Connect doesn't detect MMU3 after printer (re)boot

[firetech]

Printer model

MK4, with MMU3

Firmware version

6.0.3 (also seen in at least 6.0.1 and 6.0.2)

Upgrades and modifications

MMU3

Printing from...

Prusa Connect

Describe the bug

Every time I cold boot or reboot my MK4, Prusa Connect shows the printer as a stock MK4, without MMU3, even though the MMU3 is working perfectly fine. If I manually trigger a reconnect to Prusa Connect by either toggling the default network interface back and forth or toggling the Enable setting for Prusa Connect back and forth, Prusa Connect shows the printer as a MK4 with MMU3 after just a few seconds (toggling the MMU Unit off and back on has no effect). If nothing is done, Prusa Connect will continue showing the printer as a non-MMU3 MK4 through at least several prints.

It seems to me that the initial handshake with Prusa Connect is made too early, before the MMU3 has finished booting, so the MMU3 data isn't sent. Then, after the MMU3 has booted, the relevant data is never updated, unless the printer somehow loses connection to Prusa Connect.

This is especially annoying when using the new Prusa Connect integration in Prusa Slicer 2.8.0, as the printer isn't considered compatible with MK4ISMMU3 G-codes ("Printer model does not match") until Prusa Connect has detected the MMU3.

How to reproduce

1. (Re)boot the printer
2. Wait for Prusa Connect to detect the printer as idle
3. Notice that Prusa Connect isn't showing the MMU3 (also not the Slots item in the status bar)

Workaround:

4. Go to Settings (or Tune, if already printing) > Network > Default and press the knob twice (to toggle back and forth between Eth and Wi-Fi).
5. Wait for Prusa Connect to show the MMU3.

Expected behavior

Prusa Connect should notice the printer has an MMU3 connected after printer (re)boot without manual intervention.

Files

No response

[cozmo14047]

And if the printer is off prusa connect doesnt show mmu so when you attempt to upload to prusa connect when the printer is off it says incompatable model

[Krosta8]

I have the same issue as described. Someone on Discord told me to try reset on the printer, but that did not help at all. Which make sense regarding what firetech wrote. If I reset the printer, MMU3 is fully booted too late for Prusa Connect to recognized connected MMU3. I can not use new feature of PrusaSlicer 2.8.0 as well, because of this :-(

[atkinsonaaron]

Same issue - the MK4 printer doesn't recognize the MMU3 is installed.
This occurred with Firmware 6.0.4. The MMU3 stopped working at firmware 6.0.3

[danopernis]

Thanks for reporting. We have a fix for that scheduled for next release. The issue is caused by race condition when printer connects to Prusa Connect before MMU boots.

[danopernis]

This should be fixed in v6.1.2 via fc1b163 can you re-test please?

[Krosta8]

Yesterday I did a print and it was working correctly. Just in Prusa App I see it like without MMU (not sure if the app can show with/without MMU variant)

[cozmo14047]

Fixed for me but like Krosta8 said in the app the image is just a standered mk3.5 but on the web it shows correctly

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