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: https://eewiki.net/display/linuxonarm/BeagleBone+Black 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: > > Hi, > > 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: > > git://git.denx.de/u-boot.git > git://git.ti.com/ti-u-boot/ti-u-boot.git > > and even the u-boot source that that ships with the SDK: > > ~/ti-processor-sdk-linux-am335x-evm-04.00.00.04/board-support/u-boot-2017.01+gitAUTOINC+9fd60700db-g9fd60700db/ > > 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- > O=am335x_boneblack > > 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 > seek=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 https://groups.google.com/d/msgid/beagleboard/bea657e2-1d31-4ce3-aef5-1506cc3de2e8%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
