Bios Mods -The Best BIOS Update and Modification Source - [Request]. Advanced menu in X220 without 5-5 Beep Problem (RSA checksums and so on).
Karl Cordes - How to flash coreboot on Lenovo X220
Dima on Twitter: "Alright, AX200 is installed on ThinkPad X220. To make it possible you want to: 1. Buy an M.2 NGFF to mPCIe adapter 2. Buy MFH4 (female) to IPEX/UFL (male)
Download lenovo BIOS/UEFI drivers for lenovo X220 Tablet Laptop (ThinkPad)
Coreboot on the ThinkPad X220 with a Raspberry Pi - Tyler Cipriani