Warning when changing filament mid-print after firmware update!
I can't explain to you how well my Prusa was printing. It was running 24/7 and getting perfect prints, with a script to pause the print part way through for me to change the filament.
Worked perfectly.
Then last night I upgraded the firmware to 3.9.0 and started a new print going. It paused as it should, but then when I went to change filament (which was now hidden in a sub-menu), I clicked it and nothing happened. I tried once more just to see if it was a slip up in the menu, but still, nothing.
I eventually found that the function no longer automatically heating up the hot end for filament changes. So I manually heat up the hot end (just to 205) and do it again. This time it re-tracts ok and extrudes the new filament fine.
I go to resume print, and find that my entire hot end is now royally f**ked! After a forced retraction I've found I now have melted filament bubbling all the way up to the top of the PTFE tube!
What the hell has happened? I really can't afford down time right now!