untrusted comment: verify with openbsd-75-base.pub
RWRGj1pRpprAfgjccdgI7iLM9HLWsNAFHNMLuxR0Q4Wp5lJUp0NVmND8YxOI1NlbdZfH3mjtx7ZH58kryVLoynsi3GN9W5YqEwU=

OpenBSD 7.5 errata 013, October 31, 2024:

Updating Apple Silicon system firmware to the latest version cripples
OpenBSD.  This disabled the onboard WiFi.

Apply by doing:
   signify -Vep /etc/signify/openbsd-75-base.pub -x 013_aplsmc.patch.sig \
       -m - | (cd /usr/src && patch -p0)

And then rebuild and install a new kernel:
   KK=`sysctl -n kern.osversion | cut -d# -f1`
   cd /usr/src/sys/arch/`machine`/compile/$KK
   make obj
   make config
   make
   make install

Index: sys/arch/arm64/dev/aplsmc.c
===================================================================
RCS file: /cvs/src/sys/arch/arm64/dev/aplsmc.c,v
diff -u -p -r1.25 aplsmc.c
--- sys/arch/arm64/dev/aplsmc.c 16 Jul 2023 16:11:11 -0000      1.25
+++ sys/arch/arm64/dev/aplsmc.c 29 Oct 2024 23:04:16 -0000
@@ -250,6 +250,12 @@ aplsmc_attach(struct device *parent, str
               return;
       }

+       error = rtkit_set_ap_pwrstate(sc->sc_rs, RTKIT_MGMT_PWR_STATE_ON);
+       if (error) {
+               printf(": can't set AP power state\n");
+               return;
+       }
+
       error = rtkit_start_endpoint(sc->sc_rs, SMC_EP, aplsmc_callback, sc);
       if (error) {
               printf(": can't start SMC endpoint\n");