Good guide to build a PiTrezor? Follow below link for the project pages I used, modified firmware links and lots of other information by the project creator: https://www.pitrezor.com/2018/02/pitrezor-homemade-trezor-bitcoin-wallet.html

Here my post and two pictures of my own PiTrezor: https://bitcointalk.org/index.php?topic=5375482.msg60227545#msg60227545

If you have further questions on details about a PiTrezor, I suggest to post them in the thread where I posted mine.