Same for me: reproduced in 12.04 (with ZTE MF626 it breaks connectivity through gsm modem) and fix from comment #18 is worked for me.
usb-modeswitch version is 1.2.0+repack0-1ubuntu1
$ uname -a Linux uanote0106 3.2.0-10-generic #17-Ubuntu SMP Thu Jan 19 19:04:20 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
Same for me: reproduced in 12.04 (with ZTE MF626 it breaks connectivity through gsm modem) and fix from comment #18 is worked for me.
usb-modeswitch version is 1.2.0+repack0- 1ubuntu1
$ uname -a
Linux uanote0106 3.2.0-10-generic #17-Ubuntu SMP Thu Jan 19 19:04:20 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux