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Date:      Tue, 14 Jul 2015 12:09:06 -0700
From:      Tim Kientzle <tim@kientzle.com>
To:        Leonardo Fogel <leonardofogel@yahoo.com.br>
Cc:        freebsd-arm@freebsd.org
Subject:   Re: RPi won't boot 10.2-BETA1
Message-ID:  <F9658058-9F1C-4335-BD64-5A5B8A79CAB7@kientzle.com>
In-Reply-To: <1436808326.55378.YahooMailBasic@web120802.mail.ne1.yahoo.com>
References:  <1436808326.55378.YahooMailBasic@web120802.mail.ne1.yahoo.com>

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> On Jul 13, 2015, at 10:25 AM, Leonardo Fogel =
<leonardofogel@yahoo.com.br> wrote:
>=20
>> Does anybody see what I am missing here?  Thanks for any suggestions.
>=20
> I've got a similar error trying to boot the BBB image. As I understand =
it, the image itself is broken.
> On the U-Boot> prompt, you can type the command 'fatls mmc 0' to list =
the FAT content. You'll see there isn't any kernel image,

FreeBSD images boot ubldr from U-Boot.  ubldr then loads the
kernel from UFS.  It's easier to chain-load through FreeBSD=E2=80=99s
loader than to teach U-Boot how to configure the FreeBSD kernel.

ubldr is basically just FreeBSD=E2=80=99s loader(8) except that it is
designed to boot from a system using U-Boot rather than a system
running a PC BIOS.  It knows how to read configuration files
from UFS that can be used to load modules and otherwise
configure the kernel before it boots.

ubldr also knows how to read the kernel and FDT from UFS,
which simplifies upgrades.  (There are variations, of course.
On RPi and RPi2, the FDT is actually read from FAT by the
RPi firmware before U-Boot loads.  The firmware adjusts
the FDT which is then accessed at a known position in memory
by U-Boot, ubldr, and the kernel.)

Yes, this is different from other systems:  U-Boot knows how
to read e2fs and how to configure a Linux kernel, so an additional
boot stage is unnecessary.  Other systems forego boot-time
configuration entirely.

> the filenames are not in the "canonical" form, and

I=E2=80=99m not sure what you mean by this.

> (BB-)uEnv.txt is empty.

An empty uEnv.txt is expected.

You can put U-Boot commands there if you need to customize U-Boot
operation.  Most people don=E2=80=99t.

If it=E2=80=99s missing, then U-Boot prints some warnings, so =
distributions typically
put an empty file there.

Tim






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