From: William Hermans <[email protected]> Reply-To: <[email protected]> Date: Monday, April 28, 2014 at 3:02 PM To: <[email protected]> Subject: Re: [beagleboard] Re: Booting Archlinux from microSD (again)
> 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. In the end, I think it all comes down to semantics. You are correct in that you can boot from your SDCard without pressing the boot button and I'm not disputing that. What is happening is that the bootrom is loading the eMMC MLO, which loads the eMMC u-boot, which loads the SDCard uEnv.txt, which modifies the u-boot env and then boots from the SDCard. No need to press any boot button. Now if the MLO or u-boot on the eMMC does not work, it will be necessary to use the u-boot on the SDCard and that is the purpose of the boot button. Thus is is not possible to brick the BBB. Anyway, as I said the Robert, I cannot even remember why we went down this road. Regards, John > > > 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 >>>>> > >--- >>>>> > >You received this message because you are subscribed to the Google >>>>> Groups >>>>> > >"BeagleBoard" group. >>>>> > >To unsubscribe from this group and stop receiving emails from it, send an >>>>> > >email to [email protected] >>>>> <mailto:beagleboard%[email protected]> . >>>>> > >For more options, visit https://groups.google.com/d/optout. >>>> > >>>> > >>>> > -- >>>> > For more options, visit http://beagleboard.org/discuss >>>> > --- >>>> > You received this message because you are subscribed to the Google Groups >>>> "BeagleBoard" group. >>>> > To unsubscribe from this group and stop receiving emails from it, send an >>>> email to [email protected] >>>> <mailto:beagleboard%[email protected]> . >>>> > For more options, visit https://groups.google.com/d/optout. >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google Groups >>> "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
