mirror of
https://github.com/u-boot/u-boot.git
synced 2025-04-17 10:24:49 +00:00
ad3ec11b39
The Acer Iconia A500 is a tablet computer designed, developed and marketed by Acer Inc. It is powered by 1 GHz Nvidia Tegra 2 processor and 1GB DDR2 RAM. The A500 is sold with 64 GB, although both 16 GB and 32 GB models are available. Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
125 lines
4 KiB
ReStructuredText
125 lines
4 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
|
|
|
|
U-Boot for the Acer Iconia Tab A500
|
|
===================================
|
|
|
|
``DISCLAMER!`` Moving your Acer Iconia Tab A500 to use U-Boot assumes
|
|
replacement of the vendor Acer bootloader. Vendor Android firmwares will no
|
|
longer be able to run on the device. This replacement IS reversible.
|
|
|
|
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 picasso_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.
|
|
|
|
Permanent installation can be performed either by using the nv3p protocol or by
|
|
pre-loading just built U-Boot into RAM.
|
|
|
|
Processing for the NV3P protocol
|
|
********************************
|
|
|
|
.. 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 a500
|
|
|
|
The script will produce a ``repart-block.bin`` ready to flash.
|
|
|
|
Processing for pre-loaded U-Boot
|
|
********************************
|
|
|
|
The procedure is the same, but the ``--split`` argument is used with the
|
|
``re-crypt.py``. The script will produce ``bct.img`` and ``ebt.img`` ready
|
|
to flash.
|
|
|
|
Flashing U-Boot into the eMMC
|
|
-----------------------------
|
|
|
|
``DISCLAMER!`` All questions related to NvFlash 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 either by using the nv3p protocol or by
|
|
pre-loading just built U-Boot into RAM.
|
|
|
|
Flashing with the NV3P protocol
|
|
*******************************
|
|
|
|
Nv3p is a custom Nvidia protocol used to recover bricked devices. Devices can
|
|
enter it either by pre-loading vendor bootloader into RAM with the nvflash.
|
|
|
|
With nv3p, ``repart-block.bin`` is used. It contains BCT and a bootloader in
|
|
encrypted state in form, which can just be written RAW at the start of eMMC.
|
|
|
|
.. code-block:: bash
|
|
|
|
$ nvflash --setbct --bct picasso.bct --configfile flash.cfg --bl bootloader.bin
|
|
--sbk 0xXXXXXXXX 0xXXXXXXXX 0xXXXXXXXX 0xXXXXXXXX --sync # replace with your SBK
|
|
$ nvflash --resume --rawdevicewrite 0 1024 repart-block.bin
|
|
|
|
When flashing is done, reboot the device.
|
|
|
|
Flashing with a pre-loaded U-Boot
|
|
*********************************
|
|
|
|
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.
|
|
|
|
While pre-loading U-Boot, hold the ``volume down`` button which will trigger
|
|
the bootmenu. There, select ``fastboot`` using the volume and power buttons.
|
|
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 MicroSD and then on
|
|
eMMC. Additionally, if the Volume Down button is pressed while booting, the
|
|
device will enter bootmenu. Bootmenu contains entries to mount MicroSD and eMMC
|
|
as mass storage, fastboot, reboot, reboot RCM, poweroff, enter U-Boot console
|
|
and update bootloader (check the next chapter).
|
|
|
|
Flashing ``repart-block.bin`` 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 MicroSD card
|
|
and insert it into the tablet. Enter bootmenu, choose update the bootloader
|
|
option with the Power button and U-Boot should update itself. Once the process
|
|
is completed, U-Boot will ask to press any button to reboot.
|