The US government has launched an investigation into the state of the US smartphone market’s security practices. Two agencies – telecoms regulator FCC and the Federal Trade Commission – have sent letters to manufacturers and carriers, asking for details on how security patches are reviewed and pushed to devices. The background to the probe involves Apple’s recent court appearances contesting an FBI request for a backdoor to an iPhone at the center of a terrorism investigation, as well as Android’s infamously fractured ecosystem, which has resulted in known vulnerabilities and apathetic carrier updates. The carriers are loath to push untested updates to the devices they server in case they somehow damage the phone’s baseband connectivity, or impact the custom software…