Samsung Exynos Generic ARMv8 Boards (for mobile devices)
Overview
This document describes how to build and run U-Boot for Samsung Exynos generic boards. Boards are expected to boot with a primary bootloader, such as S-BOOT or S-LK, which hands off control to U-Boot. Presently, only ARMv8 devices are supported.
The U-Boot image is built with all device tree blobs packed in a single FIT image. During boot, it uses simple heuristics to detect the target board, and subsequently the appropriate FDT is selected.
Installation
Building
If a cross-compiler is required, install it and set it up like so:
export CROSS_COMPILE=aarch64-linux-gnu-
Then, run the following commands to build U-Boot (replace <dtb> with the
upstream DTB path for the target device):
make O=.output exynos-mobile_defconfig
make DEVICE_TREE=<dtb> O=.output -j$(nproc)
If successful, the U-Boot binary will be present in .output/u-boot.bin.
Preparation and Flashing
Since U-Boot supports multiple boards, and devices have different requirements, this step will vary depending on your target.