>>jovial+Ma
> The solution to this is Tow-Boot: a distribution of U-Boot that can be put in that flash chip. With this the U-Boot firmware can just be treated like system firmware and be updated through fwupd independent of what distributions ship. This would work not only for the PinePhone Pro, but would also enable things like installing your preferred Linux distribution on a PineBook Pro by popping in a flash drive with a UEFI installer, much like you can on any other laptop.
SPI + Tow-Boot would have standardized the boot process and made it more robust.