Installing OpenBSD (-current) on the Pine A64-LTS model

This is a short guide for installing the OpenBSD latest snapshot on the Pine A64-LTS SoC board.
The official installation instructions are present here.

Contents Requirements Flash minirootXX.img Add *.dtb file Boot and install OpenBSD Readd and reflash BOOT partition

Requirements

This guide assumes that this is the first ever SoC computer that the reader has ever seen in life and has no clue how to even connect to this device.
This guide is designed for a basic introduction to working with SoC boards, along with the components needed for connecting (via a serial console):

• Pine A64-LTS (along with a power supply)
• USB to TTL converter (cp2102)(needed for serial console access, also available on amazon)
• micro-sd card (+ card reader, to read the micro-sd card from laptop/desktop)
• Access to another (unix/linux) computer for writing to the micro-sd card (this guide uses a linux computer to install OpenBSD on the pine, so the tty/mmcblk devices will be reflecting the linux nomenclature).

Flash minirootXX.img

• Download minirootXX.img for the arm64 machines (Pine A64 is an armv8/aarch64 machine).
• Put the micro-sd card in the card reader and connect it to the laptop. Make sure the the partitions are unmounted.
  • If this is the only mirco-sd card and in a dedicated card reader, it will most likely be found on /dev/mmcblk0
• Flash the minirootXX.img:

  dd if=minirootXX.img of=/dev/mmcblk0 bs=1M status=progress
  

• After flashing there will be BOOT partition of size 4MB i and a ufs partition of size 14MB.
• Download u-boot-aarch64-YYYY.MMpX.tgz from https://ftp.openbsd.org/pub/OpenBSD/snapshots/packages/amd64/ and extract the file .../share/u-boot/pine64-lts/u-boot-sunxi-with-spl.bin
• Flash the file u-boot-sunxi-with-spl.bin with the correct batch size and seek:

  dd if=u-boot-sunxi-with-spl.bin of=/dev/mmcblk0 bs=1024 seek=8
  

  • The seek is to format the starting of the disk so that the machine can boot correctly.

NOTE: The download links are for amd64, even though the machine is arm64, as the package is actually an arm64 package. The amd64 links are used as they are updated and compiled more frequently.

Add sun50i-a64-pine64-lts.dtb

• Download the file dtb-X.YYpZ.tgz from https://ftp.openbsd.org/pub/OpenBSD/snapshots/packages/amd64/ and extract the file .../share/dtb/arm64/allwinner/sun50i-a64-pine64-lts.dtb
• Mount the BOOT partition of the micro-sd card and copy the *.dtb file into a folder called allwinner, and make a copy of ALL FILES in the boot partition (needed again in step 4, so this creates a backup):

  mkdir -p /tmp/tmpmnt
  mount /dev/mmcblk0p1 /tmp/tmpmnt
  mkdir -p /tmp/tmpmnt/allwinner
  cp sun50i-a64-pine64-lts.dtb /tmp/tmpmnt/allwinner
  cp -r /tmp/tmpmnt ~/
  umount /tmp/tmpmnt
  

Boot and install OpenBSD

• Insert the micro-sd card into the pine.

• OpenBSD does not support HDMI I/O for the Pine A64 LTS so a serial console (the usb to ttl conenctor) is needed to connect to the board.

• This is the UART connector for the pine, connect it to the RIGHT side pins, as shown in the picture (connecting to the left side can mess up voltages).

  • THE TXD pin of the connector connects to the RXD pin of the board and the RXD connects to the TXD pin [RXD - receiver, TXD - transmitter].
  • Remove the RXD pin of the board before booting. This means no data can be sent while booting. Connecting the wire during the boot phase can mess up voltages.
  • Reconnect the RXD pin of the board after booting has finished.

• Connect the usb to your machine and to access the console you can use two commands cu or screen

• I will be using screen as that comes default in most linux distributions

• The serial console attaches itself to ttyUSB0 in most cases and can be connected via

  screen /dev/ttyUSB0 115200
  

  • Don't forget to hard-boot the machine after connecting the serial console so that you can begin the boot process

Re-add u-boot.bin and sun50i-a64-pine64-lts.dtb and re-flash u-boot-sunxi-with-spl.bin

• Now that you have finished the installation on sd0, if you try to reboot the machine you will end up with the following error

  DRAM: 0 MiB
  ### ERROR ### Please RESET the board ###
  

• The reason is that the installation removes the u-boot.bin and the sun50i-a64-pine64-lts.dtb files from the BOOT partition
• Remove the micro-sd card from the pine and connect it to your laptop (you can safely remove the card when the above error is showing)
• Now we need to copy all the files from step 2 back into the boot directory, while making sure that other vender *.dtb files are not present.
  • Anecdotal personal experience - having rpi *dtb files has made the bsd.mp kernel hang while booting, bsd.sp kernel still boots fine.

  mkdir -p tmp/tmpmnt
  mount /dev/mmcblk0p1 /tmp/tmpmnt
  cp -r ~/tmpmnt/* /tmp/tmpmnt
  rm -f /tmp/tmpmnt/*.dtb
  umount /tmp/tmpmnt
  dd if=u-boot-sunxi-with-spl.bin of=/dev/mmcblk0 bs=1024 seek=8
  

Enjoy