2021-10-17 10:45:42 +00:00
|
|
|
.. SPDX-License-Identifier: GPL-2.0+
|
|
|
|
|
.. sectionauthor:: Dzmitry Sankouski <dsankouski@gmail.com>
|
|
|
|
|
|
|
|
|
|
Samsung 2017 A series phones
|
|
|
|
|
============================
|
|
|
|
|
|
|
|
|
|
About this
|
|
|
|
|
----------
|
|
|
|
|
This document describes the information about Samsung A(7/5/3) 2017 midrange
|
|
|
|
|
phones and u-boot usage steps.
|
|
|
|
|
|
|
|
|
|
U-Boot can be used as a chain-loaded bootloader to replace Samsung's original SBOOT bootloader.
|
|
|
|
|
It is loaded as an Android boot image through SBOOT.
|
|
|
|
|
|
|
|
|
|
Phone specs
|
|
|
|
|
-----------
|
2022-01-07 19:12:55 +00:00
|
|
|
A3 (SM-A320) (a3y17lte)
|
2022-01-19 16:06:07 +00:00
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^
|
2021-10-17 10:45:42 +00:00
|
|
|
- 4.7 AMOLED display
|
|
|
|
|
- Exynos 7870 SoC
|
|
|
|
|
- 16GB flash
|
|
|
|
|
- 2GB RAM
|
|
|
|
|
|
|
|
|
|
.. A3 2017 wiki page: https://en.wikipedia.org/wiki/Samsung_Galaxy_A3_(2017)
|
|
|
|
|
|
2022-01-07 19:12:55 +00:00
|
|
|
A5 (SM-A520) (a5y17lte)
|
2022-01-19 16:06:07 +00:00
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^
|
2021-10-17 10:45:42 +00:00
|
|
|
- 5.2 AMOLED display
|
|
|
|
|
- Exynos 7880 SoC
|
|
|
|
|
- 32GB flash
|
|
|
|
|
- 3GB RAM
|
|
|
|
|
|
|
|
|
|
.. A5 2017 wiki page: https://en.wikipedia.org/wiki/Samsung_Galaxy_A5_(2017)
|
|
|
|
|
|
2022-01-07 19:12:55 +00:00
|
|
|
A7 (SM-A720) (a5y17lte)
|
2022-01-19 16:06:07 +00:00
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^
|
2021-10-17 10:45:42 +00:00
|
|
|
- 5.7 AMOLED display
|
|
|
|
|
- Exynos 7880 SoC
|
|
|
|
|
- 32GB flash
|
|
|
|
|
- 3GB RAM
|
|
|
|
|
|
|
|
|
|
.. A7 2017 wiki page: https://en.wikipedia.org/wiki/Samsung_Galaxy_A7_(2017)
|
|
|
|
|
|
|
|
|
|
Installation
|
|
|
|
|
------------
|
|
|
|
|
|
|
|
|
|
Building u-boot
|
|
|
|
|
^^^^^^^^^^^^^^^
|
|
|
|
|
|
|
|
|
|
First, setup ``CROSS_COMPILE`` for aarch64.
|
|
|
|
|
Then, build U-Boot for your phone, for example ``a5y17lte``::
|
|
|
|
|
|
|
|
|
|
$ export CROSS_COMPILE=<aarch64 toolchain prefix>
|
|
|
|
|
$ make a5y17lte_defconfig
|
|
|
|
|
$ make
|
|
|
|
|
|
|
|
|
|
This will build ``u-boot.bin`` in the configured output directory.
|
|
|
|
|
|
|
|
|
|
Payload
|
|
|
|
|
^^^^^^^
|
|
|
|
|
What is a payload?
|
|
|
|
|
""""""""""""""""""
|
|
|
|
|
A payload file is a file to be used instead of linux kernel in android boot image.
|
|
|
|
|
This file will be loaded into memory, and executed by SBOOT,
|
|
|
|
|
and is therefore SBOOT's payload.
|
|
|
|
|
It may be pure u-boot (with loading u-boot's payload from flash in mind),
|
|
|
|
|
or u-boot + u-boot's payload.
|
|
|
|
|
|
|
|
|
|
Creating payload file
|
|
|
|
|
"""""""""""""""""""""
|
|
|
|
|
- Assemble FIT image for your kernel
|
|
|
|
|
|
|
|
|
|
Creating android boot image
|
|
|
|
|
"""""""""""""""""""""""""""
|
|
|
|
|
Once payload created, it's time for android image::
|
|
|
|
|
|
board: axy17lte: get board usable - add bootcmd and docs
U-boot is intended to replace linux kernel in android boot image(ABL), and
it's FIT payload to replace initramfs file. The boot process is similar to
boot image with linux:
- android bootloader (ABL) unpacks android boot image
- ABL sets `linux,initrd-start property` in chosen node in unpacked FDT
- ABL sets x0 register to FDT address, and passes control to u-boot
- u-boot reads x0 register, and stores it in `prevbl_fdt_addr` env variable
- u-boot reads `linux,initrd-start` property,
and stores it in `prevbl_initrd_start_addr`
In this way, u-boot bootcmd relies on `prevbl_initrd_start_addr` env
variable, and boils down to `bootm $prevbl_initrd_start_addr`.
If more control on boot process is desired, pack a boot script in
FIT image, and put it to default configuration
What done:
- Rearrange defconfig option order
- Add CONFIG_SAVE_PREV_BL_* options
- Doc updates:
- remove wrong SBOOT memory corruption note, because
memory is changed during u-boot bringup process,
not by SBOOT
- put payload on ramdisk place in abl boot image
creation step
Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com>
2022-02-22 18:49:54 +00:00
|
|
|
uboot=<path to u-boot.bin file>
|
|
|
|
|
ramdisk=<path to FIT payload file>
|
|
|
|
|
mkbootimg --base 0x40000000 --kernel_offset 0x00000000 --ramdisk_offset 0x01000000 --tags_offset 0x00000100 --pagesize 2048 --second_offset 0x00f00000 --kernel "$uboot" --ramdisk "$ramdisk" -o uboot.img
|
2021-10-17 10:45:42 +00:00
|
|
|
|
|
|
|
|
Note, that stock Samsung bootloader ignores offsets, set in mkbootimg.
|
|
|
|
|
|
|
|
|
|
Flashing
|
|
|
|
|
""""""""
|
|
|
|
|
Flash like regular android boot image.
|
