Comment by clort
11 days ago
many Bluetooth USB dongles have NVRAM, you can write the link key for a device (eg the keyboard or mouse) into the NVRAM and then when connecting, the dongle doesn't ask the Host computer for the key. I have used this to dual boot with a Bluetooth keyboard and mouse in the past.
I think the technique would be: pair in machine A (A has a link key). Then, pair again in machine B with the same dongle. Write that key into NVRAM, and machine A considers the device paired but it never gets asked for the key so just works if you plug the dongle into either machine. I don't know how the monitor thing works, does it act as a USB hub? I guess you can just leave the Bluetooth dongle plugged in there..
This sounds extremely interesting. Do you have a link for such a USB dongle and how to write the key in the NVRAM?
I have never a seen a Bluetooth adaptor without the capability. Currently this laptop has an "Intel Dual Band Wireless-AC 8265" device which reports it can store 16 keys in the NVRAM. I have used the btkey(1) program on NetBSD to read and write keys, but it is basically speaking directly directly to the adaptor so should be possible under any OS where that is possible.
https://man.netbsd.org/btkey.1
https://cvsweb.netbsd.org/bsdweb.cgi/src/usr.bin/btkey/