[PapaParrot]

That is not what was suggested,

jggimi>>You can force single-user mode by entering -s at the "boot>" prompt.

On some of these , they say "boot -s", but I have never needed to include
"boot" , just the -s as jggimi said all ways works for me as well.

http://www.openbsdsupport.org/ed_and_fstab.htm
The process:

boot -s at boot> prompt----
You will need to operate in single user mode. You can get into that mode from the boot prompt:
boot> boot -s

https://www.openbsd.org/faq/faq8.html
Boot into single user mode. This part of the process varies depending on your platform. For amd64 and i386, the second stage boot loader pauses for a few seconds to give you a chance to provide parameters to the kernel. Here you can see we pass the -s flag to boot(8):

probing: pc0 com0 com1 mem[638K 1918M a20=on]
disk: hd0+ hd1+
>> OpenBSD/amd64 BOOT 3.33
boot> boot -s