"Can anyone suggest me" means I need you to write explicit instructions and 
understand I have not read anything and I'm tricking you into doing my homework 
so I can come to America to do your job at pennies on the dollar 

Sent from Yahoo Mail on Android

From:"[email protected]" <[email protected]>
Date:Sun, Jun 21, 2015 at 11:02 AM
Subject:Re: [beagleboard] How to make BeagleBone black boot off SD card

Hi I am stuck at the same point as abdulm, Can anyone help me out with link to 
select SDCARD as boot option.


Hi,

         I am facing a problem with Beaglebone black. I am unable to boot MLO 
(and u-boot ) from SD card. When I hold the "Boot" button, only zImage is being 
taken from the SD card but still the MLO (and u-boot ) are from eMMC. It is not 
taking MLO( and u-boot) from SD card. So I deleted the MLO (and u-boot) from 
eMMC, so that it may take from SD card as second preference. But still it is 
not able to switch to SDcard and the board is not booting now. Now I am unable 
to boot the board as eMMC is corrupted. Can anyone suggest me how to change the 
boot mode without using the "boot" switch as it has no effect and how to 
restore back the eMMC or any factory settings can be done



On Thursday, December 5, 2013 1:21:23 PM UTC+5:30, William Hermans wrote:

There are actually more than 3 boots options, and among them are what you 
covered, plus SPI, Ethernet( TFTP kernel / NFS root ), USB, and I know I am 
forgetting a couple more.


To keep things in context with what you're asking however. LIke John says 
uEnv,txt  has control over how the device boots. It has a sort of round robin 
check it does when bringing the hardware up. In the case of the SD card boot, 
the uEnv.txt file is only going to know about the sd card unless specifically 
modified to override default behavior.


Now what you're talking about seems to be a flasher image type image. Which is 
to say, it is meant to flash the eMMC back to factory default, or to flash a 
newer more modern version of Angstrom or whatever image you have. If you want 
to boot exclusively off of the SD card, then you're going to have to work at it 
a bit.


A jumper switch may seem like a better idea at first ( for boot options ) but 
it really is not. uboot boot options are vast . . .


Anyways, you're going to have to ask yourself how serious you are about getting 
your device booting exclusively from the SD card. Because if you truly want to 
understand how it all works, you're going to need to understand uboot, and 
Linux  better than it appears how well you know it now. Also, there are other 
options to consider. Which Linux distro do you want to use . . . and more 
questions to be answered yet. In short, you have your work cut out for you if 
you want to learn. Weeks, and perhaps even months.



On Wed, Dec 4, 2013 at 8:43 PM, John Syne <[email protected]> wrote:



From: Gerald Coley <[email protected]>
Reply-To: <[email protected]>
Date: Wednesday, December 4, 2013 at 4:55 PM
To: "[email protected]" <[email protected]>
Subject: Re: [beagleboard] How to make BeagleBone black boot off SD card


Push and hold the boot button and apply power.


http://www.elinux.org/ Beagleboard:BeagleBoneBlack


Gerald

Let me clear something up that seems to be confusing everyone. Gerald is 
correct from a hardware point of view; however this only selects which u-boot 
environment is loaded. When the boot button is pressed, the u-boot env is 
loaded from the SDCard and when the boot button isn’t pressed, the eMMC u-boot 
env is loaded. From that point onwards the current u-boot env checks to see if 
the SDCard is installed and if it is, u-boot boots from the SDCard FAT 
partition. If the SDCard isn’t installed, it boots from the eMMC FAT partition. 
Since the u-boot env is the same on both the SDCard and the eMMC, it doesn’t 
matter if the boot button is pressed or not. It is the uEnv.txt file that 
modifies u-boot env behavior by adding a “uenvcmd” line. 


I hope I haven’t confused everyone.

Regards,

John




On Wed, Dec 4, 2013 at 3:50 PM, <[email protected]> wrote:

Good afternoon,

I don't understand how to determine whether the BBB is booting off the SD card 
or booting off the internal flash. 

Here's what happened, I installed a 4GB image from getting started section onto 
my SD card

This was the first image here:

http://beagleboard.org/latest- images



Initially I powered on by holding the button next to SD card, It booted and I 
could tell it was not the internal image, because it did not have the demo 
applications.


Next, I tried hitting the reset button to see if it will boot off the SD card 
again, nothing happened and I could not connect to the BBB any more. I scanned 
all ports and it was not available.


I tried resetting and holding down the button again, but it would not boot off 
the SD card.


Only when I take out the SD card the BBB boots into the original installation.


Does anyone know what may have caused this? This is a brand new SD card, and I 
doubt I had damaged it by resetting the BBB.


As far as I understand there are 3 booting options, 

There is booting off internal NAND which only has 70mb (or is this only a 
partition
Booting off SD card"If using BeagleBone Black and the image is meant to program 
your on-board eMMC, you'll need to wait while the programming occurs. When the 
flashing is complete, all 4 USRx LEDs will be lit solid. This can take up to 45 
minutes."


What I don't understand is how to select how the device boots. How can I make 
it boot off the SD card every time? How do I prevent it from writing to the 
NAND? I want to prevent damaging anything by overwriting the NAND and only work 
within an SD Card.


Wouldn't it have been easier to install a jumper to select which memory the 
device boots from?


Thanks,

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