I downloaded the latest Lulzbot Cura, and updated the firmware for my Mini since it mentioned something about fan hardware related updates.
Now my prints have become problematic. layer delaminations and other print quality issues. I had not changed anything else from proven files (had printed same .gcode before the firmware update). I think I have uncovered what is going on: temperature stability on the extruder. See attached temperature graphs. I have never observed previously the temperature stability problem.
How can I switch back to the previous firmware?
(EDIT: changed post subject/title, removing “in latest firmware”)