Comment by heavyset_go

The vast majority of ARM SoCs' Linux support amounts to Linux forks, and not mainline Linux support. Forks eventually stop being maintained, and quickly become outdated.

Now that I look at it, it looks like this is the case for some[1] ARM Chromebooks, too, in that they are stuck having to use the specific ChromeOS kernels that ship with images for their Chromebook models.

[1] https://github.com/RaumZeit/LinuxOnAcerCB5-311