[dragonwriter]

> The security issue isn’t that there are separate data lines, it’s that there’s a data communication channel between charger and device.

Yes, you can only eliminate the security issue by eliminate the functionality requiring communication.

You can, however, mitigate the security issue and narrow the range of potential attacks by having a dedicated-purpose channel that only is connected to capabilities related to the functionality for which it exists. Security is always a balancing act of how to mitigate the risk associated with desired functionality; shedding functionality is only the optimal solution where the risk outweighs the benefits of the functionality.