[karteum]

You can connect to 4G with your root-enabled Linux PC and a USB dongle or minipci module. Carriers don't care about your application processor, they only care about the baseband. In the case of a smartphone, you can have root access and still run the Qualcomm closed blob firmware that will drive the baseband

[astrange]

Carriers definitely care about the OS if it's a major OS, because bugs can take them down.