altosdroid: protect USB read/write when connection is null
[fw/altos] / map-server /
drwxr-xr-x   ..
-rw-r--r-- 40 Makefile.am
drwxr-xr-x - altos-map
drwxr-xr-x - altos-mapd
drwxr-xr-x - altos-mapj