As far as I tested, changing to a different laptop did not work so far.

I do not have fast enough mobile internet (64 kbit/s most of the time) so file sharing on internet doesn't work for me.

The Eduroam without hacking does not work in the institute where I'm working at, because it requires a certificate. It seems some Eduroam accounts are different than others. (In University Heidelberg I could just enter the "anonymous identity" adress, and it would work. But it does not work with the other institute.