OpenBSD

None of this worked. Will get back to it eventually.

Load the dtb

From Jonathan Gray on an OpenBSD mailing list. https://marc.info/?l=openbsd-misc&m=152363766318429&w=2

The sopine U-Boot image does not currently include the sopine device
tree as there isn't a sopine device tree in U-Boot.

Until that changes, on the msdos/efi partition create an 'allwinner'
directory, install the dtb port and copy
/usr/local/share/dtb/arm64/allwinner/sun50i-a64-sopine-baseboard.dtb
to allwinner/sun50i-a64-pine64-plus.dtb or to a different path and
change fdtfile in the U-Boot environment.

Random

# pwd
/usr/local/share/u-boot/sopine_baseboard
ix# ls
sunxi-spl.bin               u-boot                      u-boot-sunxi-with-spl.bin   u-boot.bin                  u-boot.img                  u-boot.itb
ix# dd if=./u-boot-sunxi-with-spl.bin of=/dev/rsd4c bs=1024 seek=8
dd: /dev/rsd4c: Invalid argument
546+1 records in
546+0 records out
559104 bytes transferred in 0.429 secs (1301555 bytes/sec)
ix# mount /dev/sd4i /mnt
ix# cd /mnt
ix# ls
System Volume Information   bcm2710-rpi-3-b.dtb         config.txt                  old                         u-boot.bin
allwinner                   bcm2710-rpi-cm3.dtb         efi                         pine64
bcm2710-rpi-3-b-plus.dtb    bootcode.bin                fixup.dat                   start.elf
ix# cd allwinner/
ix# ls
sun50i-a64-pine64-plus.dtb       sun50i-a64-pine64.dtb            sun50i-a64-sopine-baseboard.dtb  sun50i-h6-pine-h64.dtb
ix# cp /usr/local/share/dtb/arm64/allwinner/sun50i-a64-sopine-baseboard.dtb sun50i-a64-pine64-plus.dtb