I'm trying to automate the process of flashing a bootable emmc (NAND) on my 
beagle bone black. I've pin strapped the board to boot using bootp/dhcp - 
the kernel that gets loaded by the u-boot.img (that was pulled in via 
dhcp+tftp) uses an initramfs as the basis of writing the MLO, (a different) 
u-boot.img and root file system (containing zImage and uEnv.txt) to 
emmc/NAND. This all works and when I restart the beagle bone black it boots 
as I expect. Hooray for automated emmc flashing.

However my problem is that I can't seem to hand roll a version the the MLO 
and u-boot.img that I flash to NAND. What I'm using right now are copies I 
found of these two files in the debian images distributed here: 
https://beagleboard.org/latest-images (These images tend to contain 
filesystems with /opt/backup/uboot/MLO and /opt/back/uboot/u-boot.img files 
existing). If I use these two boot loader files, and craft my 
/boot/uEnv.txt just so (uuid needs to be specified), then I can boot a 
couple of kernels/filesystems I have lying around successfully.

But I can't seem to reproduce these two files (MLO and u-boot.img) for my 
NAND from source. I've tried these git repos:


and even the u-boot source that that ships with the SDK:

For each of those I'm running

make CROSS_COMPILE=arm-linux-gnueabihf- O=am335x_evm am335x_evm_defconfig 
&& make CROSS_COMPILE=arm-linux-gnueabihf- O=am335x_evm

And I've even tried a different config:

make CROSS_COMPILE=arm-linux-gnueabihf- O=am335x_boneblack 
am335x_boneblack_defconfig && make CROSS_COMPILE=arm-linux-gnueabihf- 

This compilation process creates the MLO and u-boot.img files, but I can 
never seem to successfully boot anything if I use them regardless of which 
config I use.

If it helps with clarity, I am trying out MLO and u-boot.img files by 
booting from the SD card, copying over the new versions, and then running

dd if=MLO of=/dev/mmcblk1 conv=notrunc bs=128k count=1 seek=1
dd if=u-boot.img of=/dev/mmcblk1 conv=notrunc bs=384k count=2 seek=1

Note that I can always get back to the "bootable state" by writing the 
backup boot loader files that come with debian distro instead: (the sd card 
is running debian 8.7):

dd if=/opt/backup/uboot/MLO of=/dev/mmcblk1 conv=notrunc bs=128k count=1 
dd if=/opt/backup/uboot/u-boot.img of=/dev/mmcblk1 conv=notrunc bs=384k 
count=2 seek=1

How can I build MLO and u-boot.img files in order to successfully boot a 
kernel and file system of my choosing on the emmc/NAND? Is there a page 
somewhere? Any help would be appreciated.

For more options, visit http://beagleboard.org/discuss
You received this message because you are subscribed to the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to beagleboard+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
For more options, visit https://groups.google.com/d/optout.

Reply via email to