Sure! (I wrote this guide from my memories, I have no access to my laptop right now, sorry.)
To build the mainline U-boot and to create an SD-card with OpenBSD + U-boot, follow these steps:
- first you need a suitable ARM compiler toolchain, for example:
sudo apt-get install gcc-aarch64-linux-gnu - to successfully build u-boot, you will need the TPL and the BL31 blobs:
https://github.com/rockchip-linux/rkbin/blob/master/bin/rk35/rk3566_ddr_1056MHz_v1.21.bin
and
https://github.com/rockchip-linux/rkbin/blob/master/bin/rk35/rk3568_bl31_v1.44.elf - export those in your terminal session:
export BL31=/path/to/rk3568_bl31_v1.44.elf
export ROCKCHIP_TPL=/path/to/rk3566_ddr_1056MHz_v1.21.bin
- then attempt to build U-boot:
make radxa-zero-3-rk3566_defconfig
make CROSS_COMPILE=aarch64-linux-gnu-
It will result a u-boot-rockchip.bin file in your u-boot root folder.
-
then simply grab the installer image: https://cdn.openbsd.org/pub/OpenBSD/snapshots/arm64/install76.img
-
and write it to your SD-card. For example on OpenBSD host you will use a similar command:
# dd if=install76.img of=/dev/rsdXc bs=1m
But on linux host you probably want use something like:
# dd if=install76.img of=/dev/sdX bs=1m
(themin thebsparameter can be lowercase or upper case depending on your host operating system) -
then write the U-boot aswell tothe SD-card:
On OpenBSD host:
# dd if=u-boot-rockchip.bin of=/dev/sdXc seek=64
Or on Linux:
# dd if=u-boot-rockchip.bin of=/dev/sdX seek=64
Then insert the DS-card into your device, conenct your USB-serial adapter to the correct GPIO pins (consult the documentation) and open a serial monitor with the correct serial port, 1500000 baud, 8N1, then power up the board. It shoult spit tons on text on the console, then it will boot the OpenBSD loader automatically.
Hope it helps.