Beagleboard:U-boot partitioning layout 2.0
Revision as of 16:21, 3 July 2014 by RobertCNelson (talk | contribs) (document what i'm doing with eMMC on the BeagleBone Black)
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
Contents
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 thrown into ext4) uEnv.txt (priority 1)
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
uname_r = $(uname -r) cmdline = stuff passed to command line
Example Image
http://rcn-ee.net/deb/testing/2014-07-03/bone-debian-jessie-console-2014-07-03-4gb.img.xz