Here are links for the MC7700 DIP mode tools needed in Windows to flash for use in pfSense:
firmware:
http://source.sierrawireless.com/resources/airprime/software/mc7700-att-approved-firmware-swi9200x_03,-d-,05,-d-,20,-d-,03_dip/
watcher 3830:
http://www.sierrawireless.com/developer-zone/resources/airprime/development_kits/airprime-mc-series-connection-manager-dip-build-3830/
drivers 3795
http://www.sierrawireless.com/developer-zone/resources/airprime/software/airprime-mc-series-windows-drivers-dip-build-3795/