Since last Firmware Update Prints stop mid print
 
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Anthony LaCourse
(@anthony-lacourse)
Member
Since last Firmware Update Prints stop mid print

I recently updated my FIRMWARE to latest version and now have problems with prints stopping mid print. The extruder shuts off and the printer keeps going.

 

Has anyone else experienced this?

 

I also found that periodically when I tell the filament to unload the motor doesn;t push it out. I have had the machine for about 1 year. Is it common for the motor to fail that quickly?

 

Any help you can provide would be appreciated.

V/R, Tony

Posted : 02/01/2026 12:48 pm
Diem
 Diem
(@diem)
Illustrious Member

First open the nextruder idler and blow/brush out any residue then do a cold pull.  Come back if the problem persists.

Cheerio,

Posted : 02/01/2026 5:18 pm
Anthony LaCourse
(@anthony-lacourse)
Member
Topic starter answered:
RE: Since last Firmware Update Prints stop mid print

Cleared out any residue and had machine perform coldpull twice. Was able to print a small item but then the larger item stopped mid print.

Posted : 02/01/2026 10:32 pm
Diem
 Diem
(@diem)
Illustrious Member

Is this an issue with  one particular print or with all larger prints?

If you have  micrometer, measure your filament diameter in three places about 50cm apart and average the result -  is it within spec?

Try tweaking your extruder idler pressure - keep a careful count of the turns, it might be as little as a quarter turn off and you need to be able to go back accurately.

Cheerio,

Posted : 03/01/2026 8:02 am
Anthony LaCourse
(@anthony-lacourse)
Member
Topic starter answered:
RE: Since last Firmware Update Prints stop mid print

Not sure how to do all that, but I guess it will be a learning curve. Thank you for the information.

Posted : 03/01/2026 2:48 pm
ChrisHandley
(@chrishandley)
Member
RE: Since last Firmware Update Prints stop mid print

Since the firmware upgrade to latest level I've had loads of problems too.  MMU3 errors, load cell errors etc.  Upgraded from Prusa 4 to 4S, replaced thermal head and Load cell.  I've done Maintenance on MMU3. Now I'm getting a temperature sensor fault on the heatbedAny one else had problems?

Posted : 04/01/2026 11:38 am
ChrisHandley
(@chrishandley)
Member
RE: Since last Firmware Update Prints stop mid print

Prusa 4S. I've stripped MMU down and cleaned Planetary Gears. put it all back together. Think I've fixed two of the faults.  Now I've got an extruder temperature check fault.  Just told a friend who's after a 3D printer not to get a Prusa

Posted : 04/01/2026 5:06 pm
ChrisHandley
(@chrishandley)
Member
RE: Since last Firmware Update Prints stop mid print

Got Prusa 4S printer working again.  Downgraded Firmware down to 6.2.6. Done a dummy print, overriding  sensors. with no filament. Re-run calibrations and set hardware as required. i.e MMU, 4S and high flow nozzle

Looks like Firmware 6.4.0 causes numerous problems that don't clear.

Posted : 04/01/2026 7:40 pm
1 people liked
LarGriff
(@largriff)
Reputable Member
RE:

 

Posted by: @chrishandley

Got Prusa 4S printer working again.  Downgraded Firmware down to 6.2.6. Done a dummy print, overriding  sensors. with no filament. Re-run calibrations and set hardware as required. i.e MMU, 4S and high flow nozzle

Looks like Firmware 6.4.0 causes numerous problems that don't clear.

But not a word from Prusa.  They’re all Gaga over the Core One.  These problems with MK4S started when some idiot(s) at Prusa decided to merge the MK4S firmware with Core One.  6.2.6 was the last unmerged, and stable, release for MK4S.

 

This post was modified 1 day ago by LarGriff

MK4S/MMU3

Posted : 05/01/2026 3:22 pm
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