apologetic much? Its funny that you mentioned updating, its in fact the case that any network operator (or potentially anyone who can afford the equipment and has the knowledge/keys for it) can upgrade the firmware of the baseband processor remotely (OTA). So you don't even have to exploit a vulnerability or use a backdoor (that people can STILL deny their existence as conspiracy theory is hilarious).

And whats the difference to other entry points in the android operating system itself, a apologist may ask? First of all you have control over this portion of the device, you can read and audit the source code and employ selinux to harden the OS. The baseband processor on the other hand does a _LOT_ of complex parsing of huge binary protocols, exactly the point where you would want to have open source auditable software, the opposite is the case: The baseband firmware is largely a black box, nobody (not even the manufacturer of your phone) has access to the source code and can independently audit the security and remove backdoors placed there by the manufacturer hinthint.

"normally, any component that has a kernel driver can already access all your data" bullshit.