Confusion galore... When the board is powered on it boots from mmc1 (eMMC) as per SRM. It loads the uBoot files (including uEnv.txt) form eMMC.
when mmc1 does not hold a valid uBoot, or when the boot button is held down it boots from mmc0 (SD-card) Most uBoot implementations work in reverse. When a valid /boot/zImage is availale on the SD-card it will default to booting Linux from SD, if not it will boot Linux from eMMC. when a reboot is issued, the board boots as previously selected. (no need to press the boot button). When the board is shutdown it resets to default (mmc1) It is pretty well documented in the SRM, but that is only valid for the uBoot phase I makes a difference when you talk about uBoot booting or Linux booting. LP On Monday, April 28, 2014 10:42:01 AM UTC+2, William Hermans wrote: > > John, what ? I have "booted" from multiple types of devices, and have > never had to hold down the power button. No modification, nothing. IN fact, > I wrote a blog post on netbooting Debian ( TFTP / NFS rootfs ) and had a > comment come back telling me this method worked for ARCH, and busybox as > well. > > > Looking at the link Robert gave, those setting in a uEnv.txt file should > work. It probably would not hurt of the OP built his / her own uboot / MLO > too . . . > > > On Sun, Apr 27, 2014 at 11:28 PM, Don deJuan <[email protected]<javascript:> > > wrote: > >> On 04/27/2014 11:09 PM, John Syn wrote: >> >> >> From: Don deJuan <[email protected] <javascript:>> >> Reply-To: <[email protected] <javascript:>> >> Date: Sunday, April 27, 2014 at 10:57 PM >> To: <[email protected] <javascript:>> >> Subject: Re: [beagleboard] Re: Booting Archlinux from microSD (again) >> >> On 04/27/2014 10:16 PM, John Syn wrote: >> >> >> From: Doug <[email protected] <javascript:>> >> Reply-To: <[email protected] <javascript:>> >> Date: Sunday, April 27, 2014 at 9:52 PM >> To: <[email protected] <javascript:>> >> Subject: [beagleboard] Re: Booting Archlinux from microSD (again) >> >> OK this does not work on Archlinux. Besides the fact Archlinux does not >> have initrd there must be some other issue holding it up. We are getting a >> serial connection hooked up to look at that. >> >> The answer about the only way was to remove a resistor is NOT a good >> answer. First of all it is not something you would do when distributing and >> image to be written on an SD card to a user. Hack your board so it works! >> No way. >> >> You asked for a solution that will work “no matter what is on the >> eMMC”. If you have u-boot on the eMMC, BBB will use it, period. No script >> or anything else for that matter will prevent this. Remove u-boot from the >> eMMC and BBB will use u-boot from the SDCard. With SYS_BOOT2 high (Boot not >> pressed), the boot sequence is MMC1 (eMMC), MMC0 (SDCard), UART0, USB0. If >> SYS_BOOT2 is low (Boot button pressed) the boot sequence is SPI0, MMC0, >> USB0, UART0. >> >> Regards, >> John >> >> >> >> I would like to get this fixed but an easy answer would be to have a >> script that does a one time run of zeroing the eMMC on first boot of >> ArchLinux on the SD card. We have no reason to use the eMMC card in our >> application. I wish there was a HW switch or jumper on the BBB to disable >> it. That would make things much easier. >> >> So please don't go hacking your board, just nuke the code on the eMMC. It >> will then boot happily from the SD card. >> >> Hopefully we will find a better way so we won't have to do that. I will >> report back in a few days with any progress. >> >> On Sunday, April 27, 2014 10:15:04 PM UTC-4, Doug wrote: >>> >>> OK I asked this question before and I was never able to resolve it. >>> >>> I have an image (application) on microSD card that I want to distribute. >>> It uses Archlinux. >>> >>> I don't want the user to have to play with boot directories pushing >>> buttons or anything like that. I just want it to boot at power up. >>> >>> As long as a distribution (stock) image is on the eMMC it will not boot >>> the SD card unless the boot button is held down at power up. >>> >>> I can get around this by wiping the eMMC but I do not want a user >>> getting an image on SD and having to do that. >>> >>> Is there anything I can do on the SD card (boot record) to cause it to >>> boot directly from SD regardless of what is on eMMC. >>> >>> Debian apparently has no problem with this. It seems to be an Archlinux >>> issue. >>> >>> If therei s an answer please pass along the code or point me to it. >>> >> -- >> 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] <javascript:>. >> 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] <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> >> or why not just edit the uEnv.txt on the eMMC? >> >> It is u-boot default environment that loads the uEnv.txt file. uEnv.txt >> only augments the existing scripts already present in the u-boot >> environment. Nothing that you do to the uEnv.txt will prevent BBB from >> using the u-boot on the eMMC. >> >> Regards, >> John >> >> >> -- >> 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] <javascript:>. >> 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] <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> >> hmm strange >> >> -- >> 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] <javascript:>. >> 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.
