@sven write-up is good.
Here is another one from tlaurion. Explains how to start from scratch to build heads. (Need to replace board with t430, not x230 as in write up but otherwise same).
I used this Tigard flasher, with a Pomonda soic clip. It works well out of the box and doesn’t require any modifications. The Pomona soic clips are more expensive but better quality than the cheap ones you get from China. I have used both.
There are two chips u49 and u99 that need flashing. The write up on skulls isn’t too bad for this part of the process. If you follow the skulls writeup and use a raspberry pi make sure you check your pinout, don’t just use the one they have. Pinouts change between raspberry pi versions. Also double check the flashrom pinout as per manufactures datasheet once you have identified which ones you have.
Unfortunately with the T430 you need to pull the whole system apart to get access to them. unlike the x230 they are easier to access. There is a good service manual that guides you through each step. My suggestion is to take photos along the way and to have a good method to sort and remember which screws went where.
Good luck.