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Date:      Fri, 3 Jul 2015 12:00:26 -0700
From:      Tim Kientzle <tim@kientzle.com>
To:        Glen Barber <gjb@FreeBSD.org>
Cc:        Hellmuth Michaelis <hm@hellmuth-michaelis.de>, freebsd-arm <freebsd-arm@FreeBSD.org>
Subject:   Re: Once Booted from MMC, eMMC not found
Message-ID:  <2608C773-A5D6-4828-8984-EB1A4205197F@kientzle.com>
In-Reply-To: <20150703044622.GE6532@FreeBSD.org>
References:  <1435812471361-6022231.post@n5.nabble.com> <20150702050306.GD45214@FreeBSD.org> <20150702050634.GE45214@FreeBSD.org> <462071B7-1D51-45CC-B69C-E59EA36DA729@me.com> <6C705C95-D95D-4207-B23A-01CD0E583426@hellmuth-michaelis.de> <20150702143542.GD53770@FreeBSD.org> <9012912E-229D-4F70-9CCD-A156E80D6CED@kientzle.com> <20150703044622.GE6532@FreeBSD.org>

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> On Jul 2, 2015, at 9:46 PM, Glen Barber <gjb@FreeBSD.org> wrote:
>=20
> Hi Tim,
>=20
> On Thu, Jul 02, 2015 at 09:40:22PM -0700, Tim Kientzle wrote:
>>> On Jul 2, 2015, at 7:35 AM, Glen Barber <gjb@FreeBSD.org> wrote:
>>>=20
>>> I'm curious - is this even necessary to do anymore?
>>>=20
>>> My latest tests (11-CURRENT and 10-STABLE) of BeagleBone Black =
images
>>> "just boot."
>>>=20
>>> Maybe I don't understand what this script is supposed to fix.  Can
>>> someone clarify that for me?
>>=20
>> The script just copies a running system booted from SD onto the eMMC =
so that a BBB can boot without an SD card.
>>=20
>> The script just does the following:
>>  * Erases the eMMC
>>  * Reformats it
>>  * Copies boot files from SD to eMMC
>>  * Copies / from SD to eMMC (excluding a few things like /usr/src, =
/usr/obj that are unlikely to fit)
>>  * Tweaks a few configuration parameters on the copied system
>>=20
>=20
> Ah, okay, this is the part I was missing.  I misunderstood what the =
eMMC
> did overall, and wasn't sure how this interacted with the system in
> whole.

The eMMC chip is connected to the second SD/MMC interface on the SoC.  =
To the kernel, it should look just like a second SD/MMC card on the =
second interface.

BBB can boot from eMMC to create a nice self-contained system.  At one =
time, Crochet=E2=80=99s BBB images could be easily copied to eMMC to =
boot from there without an SD card, but this doesn=E2=80=99t seem to =
work anymore due to changes in FreeBSD somewhere.

I stopped using the eMMC for booting myself simply because 2GB wasn=E2=80=99=
t enough for the things I was trying to do.  There are now BBB with 4G =
eMMC chips, so that may be worth looking into again.

Tim







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