Fun fact, did you know the T480 has a UART on the headphone jack?

https://libreboot.org/docs/install/t480.html#uart-t480-only.-not-t480s

I documented this just now, using notes from Mate Kukri. Only T480, not the S model (T480s) for now.

The EC firmware can set up a UART on the headphone jack. You first need to solder some jumpers as indicated.

On the S model there's a mux instead and you have to solder a switching IC; not yet documented, or supported.

I'm doing revisions to Libreboot 20241206. Will have rev8 finished and uploaded soon.