Before you do anything. Make a decision as to whether you just want Core Boot. Or If you intend to use Heads.
Heads being the feature, use a Nitro Key or Librem Key to verify that the computer has not been tampered with. Installing Heads requires that one open the laptop and do a hardware Flash of the Chips. GitHub - merge/skulls: pre-built coreboot images and documentation on how to flash them for Thinkpad Laptops
I say that because, if one has already applied 1vyrain, it might not be possible to do the hardware Flash without gorking the MOBO.
Notice also that one must be careful as to which Intel BIOS/EFI is installed before installing either one of these things.
I read there is a another program that is called 'Anti-Evil Maid" and I know nothing about it. If it works, and can work with 1vyrain.
So do a bit of survey first as to what you want to be like when you finish.
I am hoping someone will come along now and talk about actually installing and using “Anti-Evil Maid” on a Lenovo X230. Or the difficulty of keeping the encrypted key using Heads properly set (updated) , to verify that the computer has not been tampered with.
Just found: TrenchBoot Anti Evil Maid for Qubes OS