[whitehexagon]

Agreed, a very refreshing change.

I cant reccomend anything apple or android based, but the PinePhone has some reasonable low-level documentation on itś SoC (Allwinner A64). And there are a great series of tutorials of how Apache Nuttx was ported to the PP. Here's one of the earlier ones: https://lupyuen.org/articles/uboot

I've been working through them myself but still dont understand the boot process, and a long way from radio chip functionality. But I suspect you'll find radio chips quite locked down, since they are licensed for connection to mobile networks. Often there is just a unknown binary blob running the show.

[rramadass]

Nice, thank you.

My introduction to this subject was through Harald Welte's work on OpenMoko (i still have an old one lying around somewhere) but after the explosion of iPhones/Android phones have not kept apace. Here is Harald's old but still informative presentation Anatomy of smartphone hardware: Dissecting contemporary cellphone hardware - https://media.ccc.de/v/25c3-3008-en-anatomy_of_smartphone_ha...

Also you might find Roger Ye's old book Embedded Programming with Android: Bringing Up an Android System from Scratch pretty useful.