Indeed, I was mistaken. Here’s a one-liner to install the latest version (replaces step 2):
wget https://source.puri.sm/Librem5/uboot-imx/-/jobs/399069/artifacts/raw/debian/output/u-boot-librem5_2022.10-librem5.1_arm64.deb && sudo apt install ./u-boot-librem5_2022.10-librem5.1_arm64.deb