Comment # 10 on bug 905893 from Bruno Pesavento

An alternate solution that is device-independent and preserves the internal
microSD at the cost of a delay when using other usb memories is booting with
the following kernel parameters:

usb_storage.option_zero_cd=2 usb_storage.delay_use=60

A 40-60s delay is needed to allow ModemManager to engage the modem without
interference from usb-storage.
Boot _without_ the UMTS stick, plugin the stick after the login prompt.
Tested with Huawei e156G on openSUSE 13.2 with kernel 3.16.6 and 3.17.3