On Sun, Apr 4, 2021 at 10:46 AM Drew Fustini <[email protected]> wrote: > > On Sat, Apr 3, 2021 at 8:40 AM Dennis Lee Bieber > <[email protected]> wrote: > > > > On Fri, 2 Apr 2021 14:36:51 -0600, in gmane.comp.hardware.beagleboard.user > > John Allwine <john-/83Ax2S01hhWk0Htik3J/[email protected]> wrote: > > > > >That said I still don't fully understand the problem. Where is U-boot > > >stored? I'm booting from a microSD card and using that card in one board > > >works, but didn't when I switched to this other board. Does it not pull > > >that data from the microSD card? Is it reading from the eMMC of the other > > >board? > > > > As I understand the process... Unless the boot-select button is held > > down, recent images (mid-Jessie time-frame I believe) contain a u-Boot that > > checks for the uSD card. So... > > > > Without boot-select, the u-Boot on the eMMC is loaded. It then > > checks > > for the presence of the uSD card, and then for a bootable system on that > > card. If such is found, the uSD card is made primary and booting > > /continues/ using the files found on the card. u-Boot is still the version > > from the eMMC. > > > > With the boot-select, the eMMC is completely bypassed and the uSD > > card > > is made primary, and u-Boot searched for on the uSD card. If found, it is > > loaded and continues booting using the uSD card. > > > > I'm not certain of when the "u-Boot loads device tree" vs "kernel > > loads > > device tree" change took place. If it was after the auto-uSD card boot > > change, one has the potential to have an eMMC u-Boot that expects the > > kernel to load device tree, while the kernel on the uSD expected u-Boot to > > load them (or if the uSD card is old enough, an eMMC u-Boot that does load > > device trees, running a kernel that expects to read the device tree files). > > > > Periodic flashing of the eMMC with current images is probably > > recommended, just to ensure the u-Boot image is up-to-date (and cleaning > > out crud that might have accumulated on the eMMC <G> ) > > It does come up on the list often that an old u-boot on the eMMC can > cause problems even when using the latest image on micro SD. > > If people just want to run from microSD, then Robert normally > recommends people delete u-boot on the eMMC: > sudo dd if=/dev/zero of=/dev/mmcblk1 count=1 seek=1 bs=128k
I should note that it is important to make sure you are using the correct mmc device for the eMMC. mmc1 may not always be the emmc. -Drew -- 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAEf4M_DfMmFif352tiThK3ze8w5R%2BX3oBk60hCCmoPP4-uiz%2BQ%40mail.gmail.com.
