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flatmax and arnout Fix rasberry Pi 64bit firmware overlay inclusion
This patch enables the inclusion of the Pi's overlays. Previously
the overlays were not included in the genimage configuration.
This patch ensures overlays are included in the sdcard (when
enabled) by defaulting to the inclusion of an empty
output/images/rpi-firmware/overlays directory in genimage cfg.

The Pi's overlays are built with the following config

After building, the dtbo files are present in the
output/images/rpi-firmware/overlays directory but not added
to the sdcard because they are missing from the genimage cfg

Signed-off-by: Matt Flax <>
Reviewed-by: "Yann E. MORIN" <>
[Arnout: fix indentation, and add comment explaining why an empty
         directory is created.]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <>
Latest commit 51d6d6c Jan 3, 2019


Raspberry Pi


These instructions apply to all models of the Raspberry Pi:
  - the original models A and B,
  - the "enhanced" models A+ and B+,
  - the model B2 (aka Raspberry Pi 2)
  - the model B3 (aka Raspberry Pi 3).

How to build it

Configure Buildroot

There are two RaspberryPi defconfig files in Buildroot, one for each
major variant, which you should base your work on:

For models A, B, A+ or B+:

  $ make raspberrypi_defconfig

For model Zero (model A+ in smaller form factor):

  $ make raspberrypi0_defconfig

For model 2 B:

  $ make raspberrypi2_defconfig

For model 3 B and B+:

  $ make raspberrypi3_defconfig

Build the rootfs

Note: you will need to have access to the network, since Buildroot will
download the packages' sources.

You may now build your rootfs with:

  $ make

(This may take a while, consider getting yourself a coffee ;-) )

Result of the build

After building, you should obtain this tree:

    +-- bcm2708-rpi-b.dtb           [1]
    +-- bcm2708-rpi-b-plus.dtb      [1]
    +-- bcm2709-rpi-2-b.dtb         [1]
    +-- bcm2710-rpi-3-b.dtb         [1]
    +-- bcm2710-rpi-3-b-plus.dtb    [1]
    +-- boot.vfat
    +-- rootfs.ext4
    +-- rpi-firmware/
    |   +-- bootcode.bin
    |   +-- cmdline.txt
    |   +-- config.txt
    |   +-- fixup.dat
    |   +-- start.elf
    |   `-- overlays/               [2]
    +-- sdcard.img
    `-- zImage

[1] Not all of them will be present, depending on the RaspberryPi
    model you are using.

[2] Only for the Raspberry Pi 3 Model (overlay pi3-miniuart-bt is needed
    to enable the RPi3 serial console otherwise occupied by the bluetooth
    chip). Alternative would be to disable the serial console in cmdline.txt
    and /etc/inittab.

How to write the SD card

Once the build process is finished you will have an image called "sdcard.img"
in the output/images/ directory.

Copy the bootable "sdcard.img" onto an SD card with "dd":

  $ sudo dd if=output/images/sdcard.img of=/dev/sdX

Insert the SDcard into your Raspberry Pi, and power it up. Your new system
should come up now and start two consoles: one on the serial port on
the P1 header, one on the HDMI output where you can login using a USB
You can’t perform that action at this time.