After upgrading to modemmanager-1.8rc2+1+g7e949283-1 using a Huawei E160 on a librebooted x220 as part of Pacman -Syu, the modem no longer shows on the device list in modemmanager and cannot be connected to, Downgrading to previous version fixes this issue.

Steps to recreate:
Plugin in modem
Try to connect- No devices shown/able to connect to.

Checked upstream, doesn't appear to be issues raised in Arch.