I'm a newbie, so take this with a grain of salt or as comic relief for the
experts on this website.
I don't completely understand what you're trying to do, but it sounds like
the kernel some how contains/flashes MLO/u-boot.img???
But maybe you can generate SD Card which contains everything you need (e.g.
MLO, u-boot.img, kernel, fs, uEnv.txt) and then uncomment the appropriate
line within uEnv.txt to convert that into a flasher image, and subsequently
flash the eMMC...
Instructions for where to get EVERYTHING and transfer it to SD card for the
BBB can be found here:
Once you download the u-boot source and apply all of the the obligatory
patches for BBB, you will have a buildable u-boot/SPL tree.
In lieu of generating a complete SD card image, it MAY BE possible to dd
just the MLO/u-boot.img to the eMMC on the BBB, but I think you can only do
this from a running FS on the BBB.
On Tuesday, August 8, 2017 at 6:55:12 AM UTC-5, wolfwo...@gmail.com wrote:
> 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.
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