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Logi image SD card boot

lzelze
in LOGI-Bone Discussion
Hardware: logi-bone (R1.0, 2014.03.18), BeagleboneBlack (A6)
Software: pre-built logi image (logibone_r1_ubuntu_v4.img)

My goal is to boot from SD card (which has the logi image) without holding down the Boot switch on the Beaglebone Black (BBB).

The Logi-Bone User Guide (http://valentfx.com/wiki/index.php?title=Logi-Bone_User_Guide) explains that "...the EMMC port is shared with the GPMC bus and cannot be used simultaneously with GPMC functionality...". This makes me think that BBB will boot from the SD card by default when logi-bone is attached/connected. But, it always to boot from EMMC unless I hold down the Boot switch. Maybe the User Guide meant that the EMMC is unavailable for use but EMMC is not disabled by attaching the logi-bone. Sorry if I misunderstood the information, or missed something.

So far, I've read several options:
1. Ground Pin 44 on P8 header (GPIO2_9, SYS_BOOT2) to change the boot order
2. Erase EMMC contents
3. Delete MLO file from EMMC
4. Modify uEnv.txt (to what ?)

I have not tried any of these. I don't fully understand these options (except maybe #2). Any other options? Any suggestions?

Thanks.




Comments

  • jpiatjpiat
    Hi,

    i would suggest partial option 2. In fact the emmc is partitionned in the same way as the sd card with a boot partition and a filesystem partition. On boot the booleader on the sd card tests if a bootloader exists on the eemc and then tries to boot from it. Thus the solution is to just erase the boot parition of the emmc so no bootloader is detect and the card will boot straight from the sd card. Here are the steps to follow :

    1)boot the new Ubuntu on SD card (need to press the boot button)  the
    beaglebone with logibone unplugged.
    2) When booted execute the following
    command :
    sudo dd if=/dev/zero of=/dev/mmcblk1 bs=1M count=1
    This
    will erase the first blocks of the eMMC thus disabling booting from it
    (can be restored later).
    3)Boot the beaglebone with logibone plugged
    in, you should not have to press the boot button.

    This in facts correspond to options 2, 3.

    Option 4 should be do-able, but since the last releases of debian/ubuntu for the beaglebone, the uEnv is now almost empty and its difficult to understand what the bootloader is actually doing. Writing new rules in uEnv is thus quite difficult in my opinion.

    Regards,

    Jonathan Piat


  • mjonesmjones
    @jpiat,

    Stangly my bone/logi automatically boot from the SD card without having to erase the eMMC.  When I detach the sd card it will boot from eMMC.  It seems that there is somehow a priority to boot from the SD card in my case.  I am not sure how I can figure what is causing the (wanted) behavior?
  • lzelze
    Joanthan,
    What are the steps to restore the EMMC bootloader if needed? I am going to try your steps soon. Thanks.

    mjones,
    I would prefer what you described but I don't know how to make it happen.
  • jpiatjpiat
    To restore bootloader and linux distribution you can then download an emmc_flasher image for Ubuntu or Debian that will execute from sd card and then reflash the emmc. As we only modify the boot partition, if you boot the board with the sd card without the logibone plugged in, you'll have access to the filesystem still in the emmc.

    @mjones : What image are you using ? DId you try latest Ubuntu image with those results ?
  • mjonesmjones
    I have just test and re-confirmed that I get this behavior on 2 BBB's.  Each BBB has a different angstrom versions installed on emmc.

    #1 emmc:  Angstrom v2012.12
    sd: Ubuntu 13.10 \n \l  (latest logi image)

    #2 emmc:  Debian GNU/Linux 7 \n \l
    sd: Ubuntu 13.10 \n \l  (latest logi image)

    If I remember right I only had to press the boot from sd card button on the first boot.  It then boots from sd automatically.  I could be wrong and the ubuntu version takes care of booting automatically.  

    Here is an article that talks about this issue with a proposed solution.  It seems the ubuntu has a way of taking care of this and it seems that the current LOGI ubuntu image has it built in.  At least it seems to be the case based up on my BBB boot behavior.


    Have you tried the logi configured ubuntu image on an SD card?



  • mjonesmjones
    Also this link may be helpful:
  • lzelze
    mjones,
    Thanks for links. I am using pre-built logi image (logibone_r1_ubuntu_v4.img) on the sd card. Is this the same as yours?

    After booting from sd card, the uname command shows this:
    ubuntu@arm:~$ uname -a
    Linux arm 3.8.13-bone40 #3 SMP Mon Apr 14 01:27:37 CEST 2014 armv7l armv7l armv7l GNU/Linux

  • mjonesmjones
    HI Ize.  Yes that is the version I am using.

    Maybe @jpiat can comment on why mine is working this way and yours is not.  Or if there is further testing I can do help you figure out what the difference is.


  • jpiatjpiat
    The base logi image should boot straight from the se card (may need to press the boot button). The problem of the board trying to boot from eekc all the time appeared with latest Ubuntu/Debian (with direct support for logibone). @ize you board should boot from the SD card without the modification I suggested. When did you buy your BBB and what os is loaded onto the emmc ?
  • lzelze
    Beaglebone Black board is marked as "A6" on the side of P8 header(purchased in year 2000, I think), and running
    Linux debian-armhf 3.8.13-bone30 #1 SMP Thu Nov 14 02:59:07 UTC 2013 armv7l GNU/Linux on emmc.

    Just want to clarify:
    1. Current behavior: With logi-bone board attached to BBB and SD card inserted (logi image), I have to hold down the Boot button in order to boot from SD card. If I don't press any button, it boots from emmc.
    2. Desired behavior: With logi-bone board attached to BBB and SD card inserted (logi image), no need to hold down any button, it boots from SD card --- i.e. what mjones described.

    Thanks.



  • lzelze
    Now I have the desired booting behavior, which is the same as mjones'.

    Here are what I did, in case they are helpful to others:

    1. Re-flashed emmc with the "BBB-eMMC-flasher-debian-7.5-2014-05-14-2gb.img.xz"
    2. Inserted logi image SD card
    3. Booted BBB without holding down any button --- this time it booted from SD card (logi image)
    4. (as a test) removed logi image SD card, BBB booted from emmc
    5. (as a test) re-inserted logi image SD card, BBB booted from SD card
    6. Repeated #5 with logi-bone board attached. Same desired result.

    Thank you very much @jpiat and @mjones for all your quick responses and help.


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