Unattended OpenBSD sysupgrade with encrypted RAID1

Update 2022-10-22: As of the 7.2 release, OpenBSD supports booting from an encrypted RAID 1. The procedure below therefore becomes obsolete.

If you have an OpenBSD running on (mostly) encrypted RAID1 partitions like I described in https://sven-seeberg.de/wp/?p=1018, the unattended system upgrade triggered by sysupgrade will fail after rebooting into install mode. Without interaction, the system is stuck in a reboot loop. To continue with the upgrade process, follow these instructions:

  1. When the error message appears that the system cannot continue, hit Control + C to prevent the system from rebooting. You should now have a shell.
  2. Create the sd3 device: cd /dev; sh MAKEDEV sd3
  3. Decrypt the softraid: bioctl -c C -l /dev/sd3a softraid0
  4. Hit Control + D or type exit

The unattended upgrade should continue normally without any further interaction.