In order to update my BlackBerry Q5 I wanted to use the handy Sachesi program to install all the .bar files. It proved to be more complicated than I thought.
Problem is that Sachesi does in fact use a USB connection to communicate with the BB10 device but not via some serial protocol but instead IP. Therefor the device registers itself as a USB network device and acts as a dhcp server providing the computer with a link local IPv4 in a /30 network. And here lies the problem. Sachesi doesn’t recognize your BB if there are other Network connections going.
Long story short, I disconnected LAN and Wireless, put usb0 as
iface usb0 inet manual
into /etc/network/interfaces, restarted the network-manager service and run dhclient manually
sudo dhclient -v -d usb0
Make sure that Tethering and USB mass storage are off and the device is set to Windows Mode instead of Auto or Mac.
Sometimes it does work with WiFi enabled, but I have to stick with manual dhclient.
If you get random crashes with Sachesi and XFCE just disable the xfwm4 compositor while using it.