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I cannot flash BBB eMMC

gihu

Hi all,

 

I am wroting down here these lines beacause I am quite confused, and maybe I am doing something wrong and I still don't know it.

I have a BBB revision A6. As far as I though, BBB boots from internal eMMC, and can not boot from SD, but

I doanloaded and Android image from here:

Beagleboard:Android - eLinux.org

The first thing it seems extrange for me is that eMMC is 2-GB while Android image is almost 4GB

I have used WIN32 disk imager to write the image in the SD card (I tried on winXP and win8), but when I try to flash the BBB I have no succes, I think I am following all the steps, unplug everything, plug SD card, hold down boot button (I have checked I am holding the write button) and power on while boot button is pressed, but nothing happens, 4 user LEDs are off. I have tried many times (about 20 times), I have changed the power supply, firstly that could be the problem, now I am using 5V 2.1A power supply, over the power connector.

 

But, what is even more extrange, is that if I power on the BBB with the SD card (with build-in Android image), and without presing any button, the BBB boots from SD card and starts Android, and If I power down, remove SD card and power on again, Angstrom distribution is still on BBB.

 

Has anyone seen this behave before?

Is it not posible flash this Android  image because it is larger than eMMC?

So, if BBB can`t boot from SD, what I see when I power on the BBB with the SD card, is a wrong booting?

 

I am very confused and I really appreciate your help

 

Regards,

Miguel

  • 0

    My A6 just came in yesterday, but I'm assuming that it'll be able to boot from SD just like my A5s do.

     

    Interestingly, I accidentally discovered that I don't need to push the "user" switch during power-up to boot from SD. I believe this is because the SD cards have a uEnv.txt file in the small FAT partition that tells the on-board bootloader to use the SD partitions, instead of the MMC.

     

    You'll definitely have to put that Android image on an SD card, and run from there, because you're right:it can't be installed in the MMC because it's too big. If you try to install in the onboard, some directories will point tononexistent locations, and you may not even be able to boot

     

    Ran

  • 0

    The Android image from the site you reference is a stand-alone Android image for use booting from the SD card only .. it does not, and will not program the on-board eMMC as you desire. For that you will need to search for another "eMMC flasher" image with Android, not Angstrom Linux.

  • 0 in reply to rantalbott

    Ran Talbott wrote:

    Interestingly, I accidentally discovered that I don't need to push the "user" switch during power-up to boot from SD. I believe this is because the SD cards have a uEnv.txt file in the small FAT partition that tells the on-board bootloader to use the SD partitions, instead of the MMC.

    Actually you do need to push the button to boot from SD.

     

    What you're observing is the BBB booting u-boot from eMMC, that version of u-boot seeing the files on SD and giving those priority which is then able to re-direct part of the process to SD.

    If you delete either of the files MLO or u-boot.img from the first partition on the eMMC then it will not boot from SD unless you hold the button during power on.

     

    This two step process is fine as long as the u-Boot in eMMC and SD card are the same and the kernel on both eMMC and SD are the same, if they're different it can lead to all sorts of problems like booting the kernel from eMMC and using the filesystem from SD. This can mean you boot an Angstrom linux kernel from eMMC and then try to run Android from SD with predictable results.

  • 0

    Thank you all,

     

    I am new on linux and its kernels, so I will try to read more about how it works and about its architecture.

    Any suggestions about what to read? and how to start with linux, and build kernels? (I know it is not trivial)

     

    Regards,

    Miguel

  • 0 in reply to Former Member

    This is great to know...

     

    I did re-flash the eMMC with the latest Ångström but then decided to try out Ubuntu...

    Ubuntu boots without holding the boot button and seem to work OK...

    However I've been having trouble with the USB sound dongle, the microphone does not work.

    Let me try from scratch and make sure I hold down the boot button to see if it helps... ;-)

  • 0 in reply to Former Member

    selsinork wrote:

     

    with predictable results.

    Sometimes I really miss jumpers. image

     

    Morgaine.

  • 0

    I came across this little blurb on Beagleboard:Updating The Software - eLinux.org,

    To force a boot from the microSD card, delete the MLO file in the FAT partition of the eMMC.

    You can access this when the board is connected over the USB cable and it appears as a thumbdrive.

     

    Has anyone given it a try ?

    I'll give it a try later tonight after work... ;-)

  • 0 in reply to alamorobotics

    The table on page 6 of the schematics gives the boot order for normal boot and holding the button down during a power cycle. The idea being that if it doesn't find MLO on the first device, it moves on to the next etc.

     

    I spent some time building my own uSD image to use for flashing the eMMC (sorry, the angstrom one was too slow) and my experience was that it's all to easy to end up in a state that doesn't appear to match the stated boot order. Exactly how you get there isn't clear, holding the button tends to force the right thing.

    What's not always clear is that you need to hold the button during power-on, holding it during a reset or reboot does nothing.  Once you've held the button during a power-on, the change of boot order stays in effect until you power cycle again, so in that state you'll boot to uSD on a reboot or when you press the reset button.  This obviously has the potential to confuse matters if you don't realise what's happening.

  • 0 in reply to Former Member

    selsinork wrote:

     

    What's not always clear is that you need to hold the button during power-on, holding it during a reset or reboot does nothing.

    Sometimes I really miss jumpers.

     

    Morgaine.

  • 0 in reply to morgaine

    image

    Not sure it would help here, the configuration pins are only sampled on power-up.  Yes, the days when this wasn't the case were in some ways preferable. Unless you'd just spilled a bag of 5000 jumpers on the floor image