installboot error when installing OpenBSD on VMWare

Published on 2021-06-03.

If you’re installing OpenBSD in a VMWare environment you might get the following error message at the end of the installation:

Saving configuration files... done.
Making all device nodes... done.
installboot: invalid boot record signature (0x0000) @ sector 0

Failed to install bootblocks.
You will not be able to boot OpenBSD from sd0.

This e-mail thread has the answer. Boot the installation media and go into the (S)hell. Then do this:

cd /dev ; /bin/sh MAKEDEV sd0
fdisk -iy sd0
Writing MBR at offset 0.
exit

Continue the installation as you normally would and everything should work now.