How to Erase the eMMC

Hello there,
I’m trying to better understand the BeagleBoneBlack’s boot sequence a
little better. I’ve already read the Reference Manual. My goal is to boot
my BeagleBoneBlack from uSD card and bypass the eMMC without having to
press the Boot button every time.

On Page 83, reference manual says that one way to boot straight from uSD
without having to press the boot button is to wipe the eMMC clean. How can
you do that ?

Regards
Hussam,

  1. Plug it into your PC.
  2. See it mount as a storage drive.
  3. Open it.
  4. Delete the files.

Gerald

Hi Gerald,

I’ve tried that method for erasing completely the eMMC, then inserted a uSD with an image of Angstrom and nothing happened, anything else I might be missing?

Thanks!

–Jorge.

Try holding the user button down and see if the SD card is actually bootable.

Geraln

given some confusing posts, i'd like to clarify what should be
a simple point -- applying power to the BBB while holding down the
Boot button tells the BBB to boot from the uSD card, correct? that
is, there is no need to deliberately cripple or wipe the eMMC to
simply boot from the uSD card, is there? because it seems that some
people appear to have that impression.

  do i have that about right?

rday

Basically. But if the fingers can’t handle repeatedly holding the button every time they boot, all they have to do is rename the MLO file to something like MMM.

Gerald

and that's the fundamental test, is it? the existence of a file
called "MLO" in the eMMC FAT partition? i thought as much, just wanted
to be sure.

rday

I’ve tried renaming the MLO, it didn’t boot with that eiter. The application I intend will not allow me access to the boot button so any method to boot directly to the uSD is my only option. I’ve been trying many suggestions that have appeared in the forum with no luck, is there a chance my board could be the problem here?

Thanks.

-Jorge.

You could also toggle the 'boot flag' on the eMMC.. Then it'll default
to microSD over eMMC..

fdisk ${DISK} <<-__EOF__
a
1
w
__EOF__

Regards,

ah, that's handy to know -- if the boot process does not find a
bootable partition in eMMC, it *automatically* switches to boot from
uSD? does the uSD FAT partition need to be marked bootable?

rday

>
>> Basically. But if the fingers can't handle repeatedly holding the
>> button every time they boot, all they have to do is rename the MLO
>> file to something like MMM.
>
> and that's the fundamental test, is it? the existence of a file
> called "MLO" in the eMMC FAT partition? i thought as much, just wanted
> to be sure.

You could also toggle the 'boot flag' on the eMMC.. Then it'll default
to microSD over eMMC..

fdisk ${DISK} <<-__EOF__
a
1
w
__EOF__

  ah, that's handy to know -- if the boot process does not find a
bootable partition in eMMC, it *automatically* switches to boot from
uSD?

Correct.. uSD is search after eMMC, so if eMMC fails, uSD is next...

does the uSD FAT partition need to be marked bootable?

Yeap it does, otherwise it'll fail too.. :wink:

Regards,

I just went through Robert C Nelsons excellent instructions in creating a new debian 3.8.13-bone70 uSD card. All is great and now I would like to use the Logic Supply UWN200 wireless network USB adapter. Contrary to Logic Supplies statment that all drivers are installed, I believe following the instructions at https://eewiki.net/display/linuxonarm/BeagleBone+Black do not install the drivers for this network adapter.

If someone knows of a simple set of instructions to download and make this adapter work, I would greatly appreciate it.

Thanks,

Ross

Well... If you built "bone70" as-is with no modifcations:

sudo apt-get install mt7601u-modules-`uname -r`
sudo depmod -a `uname -r`
sudo update-initramfs -uk `uname -r`

sudo reboot..

If you changed something, well..

the 3rd party source i use is here:

https://github.com/rcn-ee/mt7601u

Regards,

and you'll also have todo:

mkdir -p /etc/Wireless/RT2870STA/
cd /etc/Wireless/RT2870STA/
wget https://raw.githubusercontent.com/rcn-ee/mt7601u/master/src/RT2870STA.dat

echo "mt7601Usta" > /etc/modules-load.d/mt7601.conf

But you "choose" to buy it..

Regards,

how can you mark the uSD as bootable?

Odd question, considering the answer was in the email you referenced...

Is there a way to permanently boot from SD without physical access to the board?
this means without pressing the boot button, grounding P8.43 or similar.
as far as I have tested all the described methods ( remove boot flag, overwrite boot partition) are working only if they are executed from a system booted from sd card and not from eMMC (and this means I need to push the boot button once…)