From:  William Hermans <[email protected]>
Reply-To:  <[email protected]>
Date:  Monday, April 28, 2014 at 3:58 PM
To:  <[email protected]>
Subject:  Re: [beagleboard] Re: Booting Archlinux from microSD (again)

> I cannot even remember why we went down this road.
> 
> Me either. except that the OP was concerned about making hardware
> modifications to his/her board, and by extension having others do the same.
> Something about ARCH Linux not working in this context, when I know that it
> does.
> 
> All i really wanted to stress is that reconfiguring the BBB hardware should
> not have to be done.
You are correct. I think I was answering OP's question regarding "booting
from the SDCard no matter what is on the eMMC". Perhaps that is why I went
down this rat hole. Sorry about that.

Regards, 
John
> 
> 
> 
> On Mon, Apr 28, 2014 at 3:32 PM, John Syn <[email protected]> wrote:
>> 
>> From:  William Hermans <[email protected]>
>> Reply-To:  <[email protected]>
>> Date:  Monday, April 28, 2014 at 3:11 PM
>> To:  <[email protected]>
>> 
>> Subject:  Re: [beagleboard] Re: Booting Archlinux from microSD (again)
>> 
>>> John yeah I can not test that. All I have for a tty into uboot is an MSP430
>>> v1.5  Launchpad, with the MCU pulled to serve as a cheap way to get a
>>> console AFTER uEnv.txt has loaded. This has to do with the fact that the
>>> Launchpad is 9600 bps only, and from what I can tell uboot is hardwired at
>>> 115200 bps until uEnv.txt is read and applied.
>>> 
>>> What I mean all along when I say "boot/booting" is that I pull the kernel
>>> from x.y.z location. Which is to say I know that comes from the uSD. As for
>>> MLO / uboot ? I really do not know, what would happen if i completely erased
>>> the eMMC ?
>> Well, as Robert said, if the eMMC does not contain a MLO with a valid header,
>> the BBB will look for an MLO on the next device in the boot sequence, which
>> in this case is the SDCard.
>> 
>> Regards,
>> John
>>> 
>>> 
>>> 
>>> On Mon, Apr 28, 2014 at 3:02 PM, William Hermans <[email protected]> wrote:
>>>> upset me ? no you did not, but what Robert just said verifies what I've
>>>> been saying all along. All you need is a good uEnv.txt.
>>>> 
>>>> I am not an EE by ant stretch of the imagination, but I know I've been
>>>> "booting" from uSD since at least June last year. So, when i say "I dont
>>>> care about the schematics" I mean that MAYBE the hardware may be wired that
>>>> way, but software can and will override( or at least seems this way ).
>>>> 
>>>> End result, no having to pull x.y.z pin low, or whatever. You just use a
>>>> config line in uEnv.txt.
>>>> 
>>>> 
>>>> On Mon, Apr 28, 2014 at 12:40 PM, John Syn <[email protected]> wrote:
>>>>> 
>>>>> From:  Robert Nelson <[email protected]>
>>>>> Reply-To:  <[email protected]>
>>>>> Date:  Monday, April 28, 2014 at 12:08 PM
>>>>> To:  Beagle Board <[email protected]>
>>>>> 
>>>>> Subject:  Re: [beagleboard] Re: Booting Archlinux from microSD (again)
>>>>> 
>>>>>> 
>>>>>> 
>>>>>> On Apr 28, 2014 1:28 PM, "John Syn" <[email protected]> wrote:
>>>>>>> >
>>>>>>> >
>>>>>>> > On 4/28/14, 9:58 AM, "Robert Nelson" <[email protected]> wrote:
>>>>>>> >
>>>>>>>>> > >>
>>>>>>>>> > >> I didn¹t mean to upset you and I apologize for that. Here is a
>>>>>>>>> non book,
>>>>>>>>> > >> hands on test that may help. Change the version of your u-boot on
your
>>>>>>>>> > >> SDCard and then reboot and see which version of u-boot is
>>>>>>>>> displayed on
>>>>>>>>> > >>the
>>>>>>>>> > >> debug console.  I¹m hoping that the u-boot version in the boot
>>>>>>>>> console
>>>>>>>>> > >>will
>>>>>>>>> > >> not change or I¹ve got this completely wrong.
>>>>>>>> > >
>>>>>>>> > >As long as the bootrom finds a valid header in the MLO file, it'll
>>>>>>>> > >boot from that device. (the mmc interface wired to the eMMC has
>>>>>>>> > >priority over mmc interface wired to the microSD in the bootroom
>>>>>>>> > >order).
>>>>>>> > Hi Robert,
>>>>>>> >
>>>>>>> > Thanks for clearing this up. I was beginning to doubt myself. So to be
>>>>>>> > clear, we need to remove the MLO from the eMMC to make the BBB boot
>>>>>>> from
>>>>>>> > the SDCard?
>>>>>> That's one way, a good uEnv.txt is just easier.
>>>>> 
>>>>> Exactly, and now I cannot even remember why we went down this road ;-)
>>>>> 
>>>>> Thanks for all your help.
>>>>> 
>>>>> Regards,
>>>>> John
>>>>>> What happens if there is a valid MLO on the eMMC and there is
>>>>>>> > no u-boot on the eMMC?
>>>>>> 
>>>>>> It should halt saying can't find uboot.img
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>>> >
>>>>>>> > Regards,
>>>>>>> > John
>>>>>>>> > >
>>>>>>>> > >Regards,
>>>>>>>> > >
>>>>>>>> > >--
>>>>>>>> > >Robert Nelson
>>>>>>>> > >http://www.rcn-ee.com/
>>>>>>>> > >
>>>>>>>> > >--
>>>>>>>> > >For more options, visit http://beagleboard.org/discuss
>>>>>>>> > >---
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>>>>>>>> > >"BeagleBoard" group.
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>>>>>>>> send an
>>>>>>>> > >email to [email protected]
>>>>>>>> <mailto:beagleboard%[email protected]> .
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>>>>>>> >
>>>>>>> >
>>>>>>> > --
>>>>>>> > For more options, visit http://beagleboard.org/discuss
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>>>>>> 
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>>>>> -- 
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>>>> 
>>> 
>>> 
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> 
> 
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