Yes I apologize, I should have clarified... When I am in nickel, connecting my device via usb still works. I have removed the testing utility for now as ksm actually works fine besides the mentioned issues and I can use rmc over wifi for now!
Thank you also for the guide and for uploading KoboRoot.tgz, although luckily I do not need it, I think it is still good to leave it up just in case something might go wrong for someone else!
What doesn't work for me is the 'usb enable.sh' script I suppose. When I execute it, the USB support still shows 'disabled', that's all.
Also, after executing the 'usb enable.sh' script, ksm won't show the icons to launch nickel or koreader anymore, so I have to restart for them to reappear.
Actually maybe a pc would recognise my device but I cannot currently test that because I am using a mac. My mac also doesn't recognise my reader in plato if I use platos usb feature.
Again it is not a big issue, as I can just use nickel to transport files!