Beagleboard:U-boot partitioning layout 2.0

Goal: to create a more distro friendly default bootloader installed on the BeagleBone Black eMMC.

Based on: https://wiki.linaro.org/Platform/DeviceTreeConsolidation

Starting with u-boot: v2014.07 this will be default: Patch: https://github.com/RobertCNelson/Bootloader-Builder/blob/master/patches/v2014.07-rc4/0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch

= Partition layout =

Boot Partition
96Mb fat16 boot (unmounted usually shared as a usb gadget) MLO/u-boot.img (MLO might be hidden and u-boot.img might be thrown into ext4) uEnv.txt (priority 1) (Optional)

Rootfs Partition
(everything else) ext4 rootfs: / /boot/uEnv.txt (priority 2) /boot/dtbs/$(uname -r)/*.dtb /boot/vmlinuz-$(uname -r) /boot/initrd.img-$(uname -r) (optional)

= u-boot dtb search order = (1) Mainline: /boot/dtbs/$(uname -r)/*.dtb (2) Debian: /usr/lib/linux-image-$(uname -r)/*.dtb (3) Ubuntu: /lib/firmware/$(uname -r)/device-tree

= uEnv.txt Boot Partition /uEnv.txt = set "uenvcmd" and you have full control

= uEnv.txt Rootfs Partition /boot/uEnv.txt =

Simple: uname_r = $(uname -r)

Optional: cmdline = stuff passed to command line "quiet" mmcroot = default(/dev/mmcblk0p2 ro fixrtc) mmcroot = UUID=(actual uuid) (needs initrd.img-$(uname -r) in most cases) rootfstype = default(ext4) optargs = default(blank)

= Example Image = http://rcn-ee.net/deb/testing/2014-07-03/bone-debian-jessie-console-2014-07-03-4gb.img.xz