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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>>>>> >
>>>>> >
>>>>> > --
>>>>> > For more options, visit http://beagleboard.org/discuss
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>> 
> 
> 
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