I installed 6.1 on a new machine. A few days ago, I installed syspatches 1-4 without trouble. Today while applying patch 5, I got an error because /bsd.sp was absent. If I "cp /bsd /bsd.sp" the patch applies fine. Anyway, sometime after applying patch 4, I realized that I'd been running an SP kernel, so I added "set image bsd.mp" to /etc/boot.conf I don't think I ever deleted /bsd.sp after installation. I thought I'd mention the error message in case any of this is unexpected behavior.
$ sysctl kern.version hw.ncpufound kern.version=OpenBSD 6.1 (GENERIC.MP) #2: Tue May 2 12:58:57 CEST 2017 rob...@syspatch-61-amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/ GENERIC.MP hw.ncpufound=4 $ ls -l /bsd* -rwxr-xr-x 1 root wheel 10684150 May 8 20:09 /bsd -rw-r--r-- 1 root wheel 10756231 May 4 12:57 /bsd.mp -rw-r--r-- 1 root wheel 9431142 Apr 20 13:20 /bsd.rd -rwxr-xr-x 1 root wheel 10684150 May 8 20:09 /bsd.syspatch61 $ syspatch -l 001_dhcpd 002_vmmfpu 003_libressl 004_softraid_concat $ doas syspatch Get/Verify syspatch61-005_pf_src_... Installing patch 005_pf_src_tracking tar: Unable to access bsd.sp: No such file or directory tar: WARNING! These file names were not selected: bsd.sp Failed to create rollback patch 005_pf_src_tracking $ doas cp /bsd /bsd.sp $ doas syspatch Get/Verify syspatch61-005_pf_src_... Installing patch 005_pf_src_tracking Get/Verify syspatch61-006_libssl.tgz Installing patch 006_libssl $ syspatch -l 001_dhcpd 002_vmmfpu 003_libressl 004_softraid_concat 005_pf_src_tracking 006_libssl