@phaedrux Thanks Phaedrux, that made the behaviour clear to me. I was afraid that there was a bug or a unexpected behaviour in the firmware here. But this is logical behaviour from your point of view.
First of all, I had a typo in my initial post, it is 3.4.0beta6 not 3.3b6. (You guys are to fast. ) 🙂
I did not thought a lot about the update process to be honest. I just uploaded the needed files via the DWC, I used the firmware images I had already on my other printer with a mini5+ running 3.4.0beta6, that triggered that behaviour I believe now. The move from /sys to /firmware was something my "above shoulder ringbuffer" has dropped already. 🙂
Confusion solved, thanks!
Cheers, Chriss