PRUSA MK3 firmware update issue. Cant "calibrate" printer because fila sensor broken  

PRUSA MK3 firmware update issue. Cant "calibrate" printer because fila sensor broken

Hi! I have a mk3 since a lot of years back. Its the model with the old (ccd maybe?) filament sensor. It stopped working a while ago. I did not care, just took it away. I did not find any solutions at the time. I suppose thats why they switched to the "new sensor".
The thing is I wanted to upgrade to the newest firmware (3.14.1) and this ended up in disaster. First it switched the extruder direction. And after a full reset of the memory I am stuck with a "printer hasnt been calibrated" message and having to switch to filament sensor off every time i switch on the printer. The calibration wizard wont pass as the sensor "is missing". I tried adding the fila sensor again. No luck. I went through the manual calibration procedures. The "printer hasnt been calibrated" message still appears and makes me think that maybe it does not record the things i made in the memory. I couldnt find any info in the online assembly instructions about how to assemble this sensor, I dont know even if this sensor is supported or not by this FW. I had to surf prusa3d  for a place where they show how the cables are installed...
Any ideas on how can i work this out? There is no place in this calibration routines for broken or missing sensors? Why should it stop at a non critical issue?