Flash dhivael's SPI uboot (risky)

[craftkiller]

Note: This uboot binary was built for SPI environment only. It will not work if you try putting it on your eMMC.

What makes this build different compared to a uboot for the eMMC and are there instructions for building it myself? I'm trying to make my pinebook pro as blob-free as possible, and downloading an unsigned blob from some forum is pretty much the opposite of that :-D . I've already built uboot from https://eno.space/blog/2020/01/pbp-uboot and I use it successfully on my sd card, so I'm mostly looking for whats different for an SPI build.

Edit: Found a post on another thread mentioning the build instructions are in the git log, so nevermind.