Thanks a lot mate, I dodged a bullet there and didn't try to update ext on my own, I would've burned the fuses after I did all the work with rajkosto update

Anyway I have a few more questions
1. I'm not using SX OS and am on unofficial 5.1.0, does that mean that I can use only cartridges with fw 4.0 on them or what you wrote means that if I have any higher than fw 4.0 installed on my Switch that I'm not allowed to use cartridges at all (even if they are 3.0.2 or whatever)?
2. What kind of boot would you guys recommend? Auto boot to 5.1.0 or? What do you guys use?