Booting FreeBSD on BeagleBone Black from microSD by default

[Tim Kientzle]

> On Apr 10, 2016, at 9:06 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
> 
> 
> Does anybody have the recipe for setting things up so that power on boots 
> from the microSD card without holding down the button?

If the ROM cannot boot from eMMC, it will try to boot from microSD.

The easiest way to make the eMMC not bootable is to zero out the
boot sectors using dd:

     dd if=/dev/zero of=<eMMC device> count=100

Of course, this makes the eMMC entirely unusable.  I think you
can then reformat the eMMC (make sure it does not have a FAT
partition and does not have boot blocks) so it can be used without
the ROM trying to boot from it.

This way, the ROM will load U-Boot from microSD.

> 
> I'm pretty sure it will be simple after I know how to do it.  Google found info on the idea, but I couldn't find the file that needs editing.  It's off in uBoot land.

Even if the ROM loads U-Boot from eMMC, the default Linux
U-Boot setup on the eMMC can be configured to then load
the Linux kernel from microSD.

If you install the FreeBSD version of U-Boot to eMMC, you might be able to
do the same thing.  Personally, I find the recipe above much
simpler.

Cheers,

Tim