SDR pine64 Manjaro

[dsimic]

2) I expect that would be mask ROM for legal(political) reasons.  The only alternative that I can think of is component changes that wouldn't fit in a chip.

I'd place my bet on some fuses in the silicon, used to produce multiple SKUs from the same wafers.

By the way, AFAIK the modem in the PinePhone has a built-in DSP that runs proprietary firmware and pretty much does everything that's related to the modem's radio functionality.  The modem's built-in ARM core, running some sort of bodged Android out of the factory, acts as a bridge to the outside word, by processing the AT commands, etc.

If there's a DSP, there could be some sort of a user-accessible SDR, at least in theory.  However, I highly doubt that we'll ever be able to run something else than the factory firmware on the modem's built-in DSP.