zlacker

>>todsac+(OP)
With my Librem 5 developer hat on, I'm surprised that a SPI chip matters at all.

The Librem 5 eMMC contains a hidden "partition", which is preferred by the CPU to boot from over the "data partition" where the OS boot loader resides. It should be possible to put Tow-boot into this hidden area, and the OS stored in the data area will have no say. No separate flash chip needed to have an independent boot loader.

I wonder why the PinePhone needs a separate chip for this purpose. Is the CPU unaware of hidden areas on the eMMC?

>>dcz_se+Be
That does work on the original pinephone, the A64 SoC can boot from the mmcblk0boot0 partition. The rk3399 in the pinephone pro is way more problematic which it is why it's important to have the SPI and also have the SPI flashed from the factory.

The pinebook pro batch that has shipped now did not end up with Tow-Boot and instead has BSP u-boot on the eMMC which makes it unable to boot anything else than the shipped manjaro by default. Of course it's only the other distributions supporting this platform that have to deal with this