Bump On Thursday, October 19, 2017 at 3:03:12 PM UTC+8, Luther Goh Lu Feng wrote: > > 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 >>> <beagl...@googlegroups.com> 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/ >>> >>
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