[rbanffy]

Maybe asking politely and offering help would work better. It’s entirely possible the blob was never cleared for release as source.

In the distant past I was hired to provide programs in binary form and many clients refused to pay more for source.

[CameronNemo]

Or, you can just avoid vendors who make you beg for open source drivers.

[rbanffy]

How many competitive ARM SoC vendors that have good software higiene out there?

[CameronNemo]

Who says I have to buy an ARM SoC. I can always just check out and keep using second hand devices. Or something from Intel, if I need more power.

And to answer your question, two come to mind, NXP and Amlogic.

[rbanffy]

Are we still talking about Pine64?

As for blobs without source, the same happens with x86 all the time. If you really want a fully deblobbed computer, you can try one of the POWER boxes from Raptor.