Back when I used to have an X270 I had a shell script that ran on boot which poked a register to disable thermal throttling handling. Not at all ideal, but it made the machine usable in the absence of official Lenovo batteries which they stopped manufacturing pretty damn quickly.

I can’t recommend libreboot enough, or even heads if libreboot isn’t your speed.

Why though? Not a single reason mentioned in post about why would it be better than whatever stock BIOS the laptop is shipped with.

I’ve messed around with porting coreboot on two desktop platforms but always had the benefit of a HW serial port…

A few years ago, I got an X270 since my T430 was feeling sluggish. I'd be curious to try this!

My X270 has a 7th-gen core i5, is that Kaby Lake? Does coreboot/libreboot on the X270 need SeaBIOS or will it work with Tianocore?

Ah, todsacerdoti. ;)