Comment 2 for bug 1192297

I've another Huawei E3131 Variant - ATTR{idProduct}=="15ca" - added this line to /lib/udev/rules.d/40-usb_modeswitch.rules

ATTR{idVendor}=="12d1", ATTR{idProduct}=="15ca", RUN+="usb_modeswitch '%b/%k'"

Also added attached file to /etc/usb_modeswitch.d/ folder (contains the lines bellow):

# Huawei E3131 (Variant)
TargetVendor= 0x12d1
TargetProductList="1506"
MessageContent="55534243123456780000000000000011062000000100000000000000000000"

I think it would be nice to send this file to upstream (usb-modeswitch) developers :)