.. SPDX-License-Identifier: GPL-2.0+

U-Boot for the Ouya Game Console (ouya)
=======================================

``DISCLAMER!`` Moving your Ouya to use U-Boot assumes replacement of the
vendor bootloader. Vendor android firmwares will no longer be able to run on the
device. This replacement IS reversible if you have backups.

Quick Start
-----------

- Build U-Boot
- Process U-Boot
- Flashing U-Boot into the eMMC
- Boot
- Self Upgrading

Build U-Boot
------------

.. code-block:: bash

    $ export CROSS_COMPILE=arm-none-eabi-
    $ make ouya_defconfig
    $ make

After the build succeeds, you will obtain the final ``u-boot-dtb-tegra.bin``
image, ready for further processing.

Process U-Boot
--------------

``DISCLAMER!`` All questions related to the re-crypt work should be asked
in re-crypt repo issues. NOT HERE!

re-crypt is a tool that processes the ``u-boot-dtb-tegra.bin`` binary into form
usable by device. This process is required only on the first installation or to
recover the device in case of a failed update. You need to know your device
individual SBK to continue.

.. code-block:: bash

    $ git clone https://gitlab.com/grate-driver/re-crypt.git
    $ cd re-crypt # place your u-boot-dtb-tegra.bin here
    $ ./re-crypt.py --dev ouya --sbk <your sbk> --split

where SBK has next form ``0xXXXXXXXX`` ``0xXXXXXXXX`` ``0xXXXXXXXX`` ``0xXXXXXXXX``

The script will produce ``bct.img`` and ``ebt.img`` ready to flash.

Flashing U-Boot into the eMMC
-----------------------------

``DISCLAMER!`` All questions related to fusee-tools should be asked in the proper
place. NOT HERE! Flashing U-Boot will erase all eMMC, so make a backup before!

Permanent installation can be performed by pre-loading just built U-Boot into RAM.
Bct and bootloader will end up in boot0 and boot1 partitions of eMMC.

You have to clone and prepare fusee-tools from here: https://gitlab.com/grate-driver/fusee-tools
according to fusee-tools README to continue.

Bootloader preloading is performed to device in APX/RCM mode connected to host
PC. This mode can be entered from testpad on motherboard with device connected
to the host PC. Host PC should detect APX USB device in ``lsusb``.

U-Boot pre-loaded into RAM acts the same as when it was booted "cold". Currently
U-Boot supports bootmenu entry fastboot, which allows to write a processed copy
of U-Boot permanently into eMMC. This is how U-Boot can be preloaded using
fusee-tools:

.. code-block:: bash

    $ ./run_bootloader.sh -s T30 -t ./bct/ouya.bct --b u-boot-dtb-tegra.bin

While pre-loading U-Boot, interrupt bootflow by pressing ``CTRL + C`` (USB keyboard
must be plugged in before U-Boot is preloaded, else it will not work), input
``bootmenu`` from the keyboard and hit enter. The bootmenu will appear. There, select
``fastboot`` using the up and down arrows and enter key. After, on host PC, do:

.. code-block:: bash

    $ fastboot flash 0.1 bct.img
    $ fastboot flash 0.2 ebt.img
    $ fastboot reboot

Device will reboot.

Boot
----

To boot Linux, U-Boot will look for an ``extlinux.conf`` on eMMC. Additionally,
bootmenu provides entries to mount eMMC as mass storage, fastboot, reboot,
reboot RCM, poweroff, enter U-Boot console and update bootloader (check
the next chapter).

Flashing ``bct.img`` and ``ebt.img`` eliminates vendor restrictions on eMMC and
allows the user to use/partition it in any way the user desires.

Self Upgrading
--------------

Place your ``u-boot-dtb-tegra.bin`` on the first partition of the USB. Enter
bootmenu, choose update bootloader option with Enter and U-Boot should update
itself. Once the process is completed, U-Boot will ask to press any button to reboot.