I tried blacklisting the usb_storage module (as suggested by http://www.draisberghof.de/usb_modeswitch/#trouble) to see if this bug is caused by that kernel module. Unfortunately I then trip over this bug:
https://bugs.launchpad.net/ubuntu/+source/module-init-tools/+bug/1035739 which means that the blacklisting is ignored (to be precise the usb_storage module isn't loaded at boot but gets loaded as soon as any usb storage device is connected to the system). Great! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1175093 Title: K3520-Z mode not switched automatically To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1175093/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
