Disable firmware warning
For the Prusa MK3 3d printers you can turn off the firmware update warning.
When printing with a Prusa printer, the printer itself gave a warning every time that I had to update the firmware. But all those firmware updates add nothing to me so I disabled that warning.
In Prusa Slicer, go to the Printer Settings tab and at Start G-code delete a line of g-code. The line of code to be removed has a red arrow in the image below: