rPI went from armv6 to armv7 to armv8. CortexA76 does not even support using 32 bit kernels. Rp1 requires an armv6 32 bit kernel. There is NO kernel build on earth that would run on both an pi1 and a pi5 and no amount of efi would help. (I am ignoring the possibility of custom nasty hacks to make a polyglot kernel). We’ll have per-device images until we standardize on a single architecture or at least a subset of one.
And no, you really wouldn’t want a lowest common denominator build anyways. That would leave a lot on the table.
Yeah, I can live with images per architecture; the problem is needing an image specifically for the pi. I want the same thing as we get on x86; sure, there are separate images for i686 and x86_64, but there's not one image for Dell and one for HP and one for Lenovo and...
Well, now that the latest rPi is on the latest ARM arch, it might be possible for future rPis, unless ARM goes and changes the arch around in an incompatible way.
That's beside the point; you can build a UEFI bootloader for at least as far back as the Pi 3, but you have to stick it on an SD card because there's no on-board memory to hold it. I mostly just want enough flash built in to hold it.
rPI is quite cost optimized. That’s one of the stated goals. An extra component to buy and place on the board costs read money. Plus, an implementation of UEFI will not be tiny. It would likely would need a few MBytes of flash. That's a dollar or two already. If everybody’s requests, each of which would add a dollar or two to the board, were fulfilled, you’d be looking at a much more expensive board, and complaining about cost instead. :)
