@kinderkram the usb cable is actually from my samsung tablet
Ill borrow a windows machine at work tomorrow and check it out. I have to say that i had some trouble with my Usb(3) ports on macbook with the M4. That if i reboot the M4 from the QGC the whole systems freezes. On my old mac that doesn't occur. So i could check that as well.
I did try different rpm's, it also happend at 300rpm 900rpm,3000rpm and 9300rpm. The v3 was non responsive at arming or disarming,but did still show a active telemetry. But i had to reboot the V3 and than it would spin up, but not at the displayed rpm(despite pushing the enter key). Sometimes i just had to go up or down 50rpm to get it at the right rpm, but sometimes it stalled and one time it didn't stop spinning. But nothing consistently.
I will try it on another machine, and see if i can replicate the problem. I also wil look for some other micro usb cables to be sure.
Cheers,
Ray