Snapdragon 845¶
About this¶
This document describes the information about Qualcomm Snapdragon 845 supported boards and it’s usage steps.
SDM845 - hi-end qualcomm chip, introduced in late 2017. Mostly used in flagship phones and tablets of 2018.
U-Boot can be used as a replacement for Qualcomm’s original ABL (UEFI) bootloader. It is loaded as an Android boot image through ABL
Installation¶
Build¶
Setup CROSS_COMPILE
for aarch64 and build U-Boot for your board:
$ export CROSS_COMPILE=<aarch64 toolchain prefix>
$ make <your board name here, see Boards section>_defconfig
$ make
This will build u-boot.bin
in the configured output directory.
Generate FIT image¶
See doc/uImage.FIT for more details
Pack android boot image¶
We’ll assemble android boot image with u-boot.bin
instead of linux kernel,
and FIT image instead of initramfs
. Android bootloader expect gzipped kernel
with appended dtb, so let’s mimic linux to satisfy stock bootloader:
create dump dtb:
workdir=/tmp/prepare_payload mkdir -p "$workdir" cd "$workdir" mock_dtb="$workdir"/payload_mock.dtb dtc -I dts -O dtb -o "$mock_dtb" << EOF /dts-v1/; / { memory { /* We expect the bootloader to fill in the size */ reg = <0 0 0 0>; }; chosen { }; }; EOF
gzip u-boot
gzip u-boot.bin
append dtb to gzipped u-boot:
cat u-boot.bin.gz "$mock_dtb" > u-boot.bin.gz-dtb
Now we’ve got everything to build android boot image::
mkbootimg --base 0x0 --kernel_offset 0x00008000 \
--ramdisk_offset 0x02000000 --tags_offset 0x01e00000 \
--pagesize 4096 --second_offset 0x00f00000 \
--ramdisk "$fit_image" \
--kernel u-boot.bin.gz-dtb \
-o boot.img
Flash image with your phone’s flashing method.
Boards¶
starqlte¶
The starqltechn is a production board for Samsung S9 (SM-G9600) phone, based on the Qualcomm SDM845 SoC.
More information can be found on the Samsung S9 page.