Cascading failures of two printers after firmware upgrade
I have two Prusa MK3 at present. Originally I bought 3 Genuine Prusa, but then when I had problems getting them I bought a few from Aliexpress.
Now I no longer need to print large batches of things I have sold/given away all but one genuine and one triangle-labs clone.
Both where the same age and had the same firmware from about 4 or 5 years ago but I am unsure which version it was.
I just tried to upgrade to 3.14.1 and everything went south.
After the upgrade one of the printers did a thermal calibration and then I tried to print out something from the SD card that I regularly print. It started printing about 1/4 size. I stopped the print and told it to do an X/Y calibration. It would fail telling me there was a problem with the axis.
I read all I could on google about this and mostly people saying it was a mechanical issue and the rails or belts had a problem. I gave it a thorough mechanical service and still the same problem.
Bit more trouble shooting and I worked out that the controller thought the axis was too long and was not reaching the end in a given number of steps. Attaching the USB and using a terminal I found this
The micro steps was a nonsense value. I changed that and it would then calibrate but printed terrible. I did a factory reset and initial setup and still bad printing. Downgraded to 1.13.3 and factory reset and that printer would now print. about as good as before the upgrade.
The second printer just had a fit trying its first print after the firmware upgrade. (I did both upgrades before I discovered the problem).
Downgraded to 1.13.3. Factory reset. Would print but had the worst stringing I had ever seen. It had mild stringing before the upgrade. So I gave it a new nozzle and new PTFE tube (which it definitely needed), cleaned the rollers and the whole path.
No improvement.
I assume this is still a software/firmware issue. As as print I did off the SD card before the upgrade and one I did after the upgrade from the same file - were so wildly different. Nothing changed mechanically (until I changed nozzle/PTFE). Is there some other way to reset the EEPROM apart from the "Reset/HOLD-dial" option that does a cleaner reset? Is there some calibration that is not part of "out-of-box" setup I need to do?
Or do I just now have a fancy black and orange paperweight.