Re: Broadcom BCM2709, ARMv8, and missing CPU features

[Gunnar Wolf <gwolf@debian.org>]

Alan Corey dijo [Thu, Jul 28, 2016 at 12:22:23PM -0400]:
> Huh?  I thought they claimed they were interchangeable.  I had an
> image from my model B days 3 years ago that I booted on my 3B.  And I
> cloned a working current 3B SD card and booted a Zero from it.  There
> isn't a different Debian image for every brand of motherboard and CPU,
> they probe to see what hardware is there.  I wouldn't expect older
> images to contain drivers for newer hardware maybe.
> 
> I guess I wouldn't make too much of the jump to 64 bit just yet.  I
> remember when i386 jumped to 32 bit.  16 bit had a messy segmented
> memory addressing scheme I was glad to get away from.  I can't afford
> more than 32 bits worth of RAM anyway, especially since I've usually
> got about 4 machines running.

I'm far from an absolute expert in this area... But I am fairly
certain of what I say — That is, I have a RPi 1 and 2B, and they
cannot boot from the same images.

Keep in mind it's not different Debian images we are talking about —
"real" Debian cannot be booted on Raspberry hardware. I run a Debian
userland on top of their provided kernel (with the mystery blobs to
control its hardware), started by their mystery bootloader. And yes,
for us people coming from the x86 world, we expect similar devices to
"just work", but in ARM it *is* really a different way of doing things
per each kind of board.

I can suggest you to see the talk delivered by Martin Michlmayr some
weeks ago at DebConf on this topic:

    http://ftp.acc.umu.se/pub/debian-meetings/2016/debconf16/Debian_on_ARM_devices_2.webm