In the 1980s we downloaded games from the radio

I know audio gear that does firmware updates via audio input.

The most obscure thing I have ever seen is a device that received firmware updates by strobing the bits as light into a photodiode. You would go to a website on your phone, press upload and hold the phone in front of the thing.

There was a brief period during the late 90s/early 2000s before WiFi became ubiquitous that laptops came with IR transmitters/receivers for streaming data.

It was always touchy, slow, required an unbroken line of sight, and poorly supported by both the OS and application software, but I did make it work a couple of times. The PDAs of the time used a similar technology to send contact information (business cards) between devices.