I have a BBB which has the eMMC flashed from the microSD card using the flasher script. Therefore, the MLO and the u-boot should be idenitical.
Referencing the eewiki page[1]I backed up the MLO from the eMMC and the microSD: sudo dd if=/dev/mmcblk0 of=./mmcblk0_MLO count=1 seek=1 bs=128k sudo dd if=/dev/mmcblk1 of=./mmcblk1_MLO count=1 seek=1 bs=128k The shasums are however different: debian@beaglebone:~$ sha256sum mmcblk0_MLO 493f8723705c73c3383898658ce2b1855bbca219825198d2a23b115ce30a4ada mmcblk0_MLO debian@beaglebone:~$ sha256sum mmcblk1_MLO 51d7b68ec8eac56f6d04371c77885332e9eedc7c5434350750ba58f51e86fd56 mmcblk1_MLO Am I backing up the MLO correctly? [1] https://eewiki.net/display/linuxonarm/BeagleBone+Black#BeagleBoneBlack-SetupmicroSDcard On Thursday, October 19, 2017 at 10:35:11 AM UTC+8, Luther Goh Lu Feng wrote: > > From https://groups.google.com/d/msg/beagleboard/4HTJt7J2M8w/3qdig-7hBQAJ > > >> Next question. If I flash the eMMC using the microSD card debian > flasher > >> script, and then dd out 1MB from the eMMC and microSD, do I expect both > to > >> have the same shasum? I expect yes, since they came from the same > debian > >> image, but unless I made a mistake or there are some false assumptions > on my > >> part, I seemed to be getting different checksums > > > No... different drive geometries.. > > Just to clarify, does the above still hold true? If yes, does it mean that > different drive geometries means that the 1MB of each storage medium > contains other drive specific stuff, together with the MLO and u-boot, and > therefore results in differences in the 1MB content for each drive? > > > --Luther > On Thursday, October 19, 2017 at 3:45:14 AM UTC+8, RobertCNelson wrote: >> >> On Wed, Oct 18, 2017 at 2:41 PM, 'Luther Goh Lu Feng' via BeagleBoard >> <[email protected]> wrote: >> > Given that the eMMC and microSD has different drive geometries[1], what >> is >> > the correct way of backing up and restoring the MLO and u-boot from one >> > medium to another? eg from eMMC to microSD or from microSD to eMMC. >> >> That's incorrect, the drive geometries doesn't affect MLO/u-boot.img >> which are always in the same location on either eMMC/microSD. >> >> you can use 'dd' to extract them or just grab the "backup" versions >> found under: /opt/backup/uboot/ >> >> Regards, >> >> -- >> Robert Nelson >> https://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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/c9b334a4-527a-4108-a2d2-031c7c0bc90d%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
