Difference between revisions of "Beagleboard:U-boot partitioning layout 2.0"

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(document what i'm doing with eMMC on the BeagleBone Black)
 
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== Boot Partition ==
 
== Boot Partition ==
 
  96Mb fat16 boot (unmounted usually shared as a usb gadget)
 
  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)
+
  MLO/u-boot.img (MLO might be hidden and u-boot.img might be thrown into ext4)
  uEnv.txt (priority 1)
+
  uEnv.txt (priority 1) (Optional)
+
 
 
== Rootfs Partition ==
 
== Rootfs Partition ==
 
  (everything else) ext4 rootfs: /
 
  (everything else) ext4 rootfs: /

Revision as of 16:22, 3 July 2014

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

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