Rate how well Octoprint works with the MK4

For those of you who have used Octoprint with a Prusa MK3, and now have an MK4, how would you rate how well it works on the MK4 compared to the MK3?

5 - Way better
4 - Somewhat better
3 - About the same
2 - Not quite as good
1 - Not good at all

3 - About the same.

I starting printing from Octoprint to my new MK4 today and the only thing I miss is seeing the percent complete and time remaining on the printer display like they were on the MK3S.

1 Like

3 - About the same.

I have no issues, but I also miss being able to see the percentage complete, receive notifications for filament change, and have an estimate of the remaining print time. Prusa has already hinted that the next firmware update will include additional information on the display.


I use Octoprint with my MK3.5 (which was a MK3S+ just a week ago). I find it works OK, apart from the fact that after powering my printer I need to disconnect and then connect manually before it detects the printer.
Is that something you people experience as well?

I find that after powering down the printer OctoPrint automatically disconnects after some time (I don't know how long). After I power up the printer I have to manually connect.

It actually says it did that:
State: Offline after error
SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)

I find it missing some features that the MK4 has built-in. I would say a 3 from the Octoprint side of things being the same but a 2 from the mk4 side as we are missing newly added features.

  1. The filament runout sensor doesn't work when printing via USB - once filament runs out, the printer just continues on printing air
  2. Pause print (M601) doesn't work
  3. The Prusa firmware doesn't go into "print mode", so you cannot manage the print from the printer's LCD. This includes canceling, pausing or tuning the print, or seeing progress.
1 Like

this is contrary to what other people are saying about the MK4 on the Prusa forum here.

That same thread also indicates that PrusaResearch has stated they plan on adding more integration for connected serial hosts (like OctoPrint).

Curious if it makes a difference if you add that M601 command to the pausing commands section (under serial connection > firmware and protocol) of OctoPrint?

1 Like

Great update. Thanks.

My experience of Octoprint on the MK4 has been somewhat different to peoples experience here and I wanted to check what the differences are.

I've just got a new MK4 about four days ago and the first thing I did was build a new Octoprint for it. That was before I even opened the box.

I have two MK3S+ printers each with a Pi 3 on that are in fairly constant use, had these for 2-3 years and they have been very good. I think Octoprint is brilliant on the MK3's and is well integrated. I use a lot of custom pauses on the MK3 to stop things so I can embed nuts (I do a lot of these) and a few more recent ones on filament changes.

My experience of Octoprint on the MK4 has been utterly awful. To be very, very clear, I think this is 100% due to Prusa not implementing a chunk of the gcodes that Octoprint uses. I attach no blame to the OP community or to the developer.

I'm running the latest firmware from Prusa 6.0.2.

If I start at the top:

  1. The new menu display on the Prusa 4 when connected to OP is useless. It offers virtually no information in comparison to the MK3. There is zero point in looking at it.

  2. For some reason the MK4 will carry on printing when there is no filament in. This could be related to the filament sensor issue.

  3. Filament changes or out of filament sometimes works or sometimes doesn't. Now there is a known problem with the filament sensor that Prusa have been working on for 11 months now and still can't get a resolution.

  4. I have had issues where I pause a print to change filament and the MK4 keeps printing, them coming back to purge the extruder and goes back to print, prints a layer, comes back, purges repeat until dead.

  5. There appears to be no way to get Octotext to send alerts (or I couldn't get them to work). Really useful for out of filament or the machine is paused.

  6. Its debatable how useful the gcodes that Prusa indicate should be added to OP for things like cancelled prints. Some people seem to think they work and some people think they do nothing. They seemed to do nothing for me.

PrusaLink is a broken childs toy in comparison to Octoprint. I'd be embarrassed if I was prusa and I had put out PrusaLink. The only thing I can think of is that Prusa maybe trying to charge for PrusaLink or PrusaConnect in the future, will be a loooong time before it's fit for purpose IMHO.

Some people here seem to be happy with Octoprint on the MK4, to me OP is useless as Prusa have crippled it. If somebody has it working really well with all the issues I've stated above, please let me know what I am doing wrong.



you hit the nail on the head so to say.

one thing to ask though, did you do step 13 in their official instructions?

Yes, did all the steps, tried it with the changes in Step 13 and without. Made no difference to me.

Prusa have done their best ot pretend to support OP but in reality have screwed it over.

Hi, I have been using OctoPrint with my MK4 since it arrived in mid-April last year. In the beginning it was not "officially supported" by Prusa and the filament run-out sensor did not work. But I managed to work around that drawback. After the release of firmware 5.1, when Prusa claimed "initial support" for OctoPrint, the filament run-out sensor as well as pauses for color changes or manual MMU prints did work for me. Apart from the missing progress info on the printer's display OctoPrint on the MK4 works just the same for my use case as on my MK3S+, which I still have and use.
Are you sure that you did insert all the gcode scripts into the settings for the printer profile?

The attached screenshots shows the values in the populated fields for gcode scripts in the settings of my MK4. The other fields there are empty.

Thanks for this. I did insert them but I put the M604 at the bottom and not the top of the gcode section. Which firmware version are you using please? My printer came with 6.0 and I upgraded to 6.0.2/

I found little difference using the M601 and M602.

I have had nothing but problems with the filament sensor and the the Mk4. If I don't change the filament or I don;t pause, I can get good prints. However Its simply not reliable for me. I never get the same result twice so I'm always trying to work out whats going on.

Mind you PrusaLink is a utter pile of junk, and I'm being charitable. Despite removing my test filament changes, and recalculating the gcodes by moving the model very slightly, for some reason the MK4 keeps trying to do a filament change.

I'm very unhappy with the Mk4 and if it goes back, I may just buy a Mk3 again and use something I know and I forget the better quality. I hear that the XL suffers from the same problem, thank god I didn;t spend £4K on the five head monster.


My MK4 is on firmware 6.0.2. I did not notice any difference in behaviour to the version before that. The settings in the screenshot are what I have been using since firmware version 5.1.x.
I cannot say anything about the remote control software solutions from Prusa, because I never used any of them. I don't want any cloud solution like Connect and I think that the networking hardware that comes with the printer is outdated and underpowered compared to a Raspberry Pi, so I won't use Link neither. I was already happily using OctoPrint before Prusa introduced their remote software solutions and I saw no reason to switch, especially when I saw the frequent complaints about the transfer speed in the Prusa user forum. I use a lot of ESP microcontrollers in my network at home, but just for transferring sensor values for automations and such, not for shovelling megabytes.


Thanks for the update, you have given me hope that OP may work. PrusaLink has a number of issues with it, it's garbage and very slow as it uses the USB as storage.

I've updated my Pi to the new codes and will have anotehr try.

I really want three things from the OP

  1. Notifications that the filament has run out or the printer is paused so I can do something
  2. Reliable filament changes for new colours
  3. Reliable pauses so I can insert nuts.

If I have those I'll be OK. Should be easy :slight_smile:
Thanks again, appreciate the help


I've put the codes back in to octoprint and connected it again.

I've got a test print going, I really like the quality of the MK4 at 0.1mm. It's very, very good. I forced a filament change and printing stopped and I could change the filament on the LCD display of the Prusa. The filament sensor is still junk, it takes 20-50x pushing a length of filament into the hole and removing it along with compressed air before it triggers. I've now pulled the plenetary gears off so I can check the filament sensor as well. That was exciting.

I've seen some of your comments on the Prusa board as well. I was wondering if you had managed to get Octoprint to send alerts when the Mk4 out of filament.



OctoPrint shows when the MK4 is paused for some reason and you can resume either from OctoPrint or from the display on the printer. For alerts for filament changes I can hear the beeps of the printer from the next room. I am not aware of any alerting functionality from OctoPrint when this happens. I have a Pi cam in my enclosure and can keep an eye on the printer with that.
On the filament sensor I can only say that mine works as expected.


Interesting, I don't get Octaprint pausing for an out of filament change, so I assume you mean for a regular planned filament change. I can't find anybody who has got alerts to work for out of filament either. I was hoping they're be a clever person somewhere who has made this work.

Some of my prints are very long and run overnight, so an alerting system is good. Might be worth looking at a Raspberry Pi AI system that is trained to work out where the extruder head is :slight_smile: Perhaps a bit of overkill.

Thanks for your help