diff --git a/regress/misc/fuzz-harness/Makefile b/regress/misc/fuzz-harness/Makefile
index f02d6858c..64fbdbab1 100644
--- a/regress/misc/fuzz-harness/Makefile
+++ b/regress/misc/fuzz-harness/Makefile
@@ -3,9 +3,10 @@ CXX=clang++-6.0
 FUZZ_FLAGS=-fsanitize=address,undefined -fsanitize-coverage=edge,trace-pc
 FUZZ_LIBS=-lFuzzer
 
-CXXFLAGS=-O2 -g -Wall -Wextra -I ../../.. $(FUZZ_FLAGS)
+CXXFLAGS=-O2 -g -Wall -Wextra -Wno-unused-parameter -I ../../.. $(FUZZ_FLAGS)
 LDFLAGS=-L ../../.. -L ../../../openbsd-compat -g $(FUZZ_FLAGS)
 LIBS=-lssh -lopenbsd-compat -lcrypto -lfido2 -lcbor $(FUZZ_LIBS)
+COMMON_OBJS=ssh-sk-null.o
 
 TARGETS=pubkey_fuzz sig_fuzz authopt_fuzz sshsig_fuzz \
 	sshsigopt_fuzz privkey_fuzz
@@ -15,23 +16,23 @@ all: $(TARGETS)
 .cc.o:
 	$(CXX) $(CXXFLAGS) -c $< -o $@
 
-pubkey_fuzz: pubkey_fuzz.o
-	$(CXX) -o $@ pubkey_fuzz.o $(LDFLAGS) $(LIBS)
+pubkey_fuzz: pubkey_fuzz.o $(COMMON_OBJS)
+	$(CXX) -o $@ pubkey_fuzz.o $(COMMON_OBJS) $(LDFLAGS) $(LIBS)
 
-sig_fuzz: sig_fuzz.o
-	$(CXX) -o $@ sig_fuzz.o $(LDFLAGS) $(LIBS)
+sig_fuzz: sig_fuzz.o $(COMMON_OBJS)
+	$(CXX) -o $@ sig_fuzz.o $(COMMON_OBJS) $(LDFLAGS) $(LIBS)
 
-authopt_fuzz: authopt_fuzz.o
-	$(CXX) -o $@ authopt_fuzz.o ../../../auth-options.o $(LDFLAGS) $(LIBS)
+authopt_fuzz: authopt_fuzz.o $(COMMON_OBJS)
+	$(CXX) -o $@ authopt_fuzz.o $(COMMON_OBJS) ../../../auth-options.o $(LDFLAGS) $(LIBS)
 
-sshsig_fuzz: sshsig_fuzz.o
-	$(CXX) -o $@ sshsig_fuzz.o ../../../sshsig.o $(LDFLAGS) $(LIBS)
+sshsig_fuzz: sshsig_fuzz.o $(COMMON_OBJS)
+	$(CXX) -o $@ sshsig_fuzz.o $(COMMON_OBJS) ../../../sshsig.o $(LDFLAGS) $(LIBS)
 
-sshsigopt_fuzz: sshsigopt_fuzz.o
-	$(CXX) -o $@ sshsigopt_fuzz.o ../../../sshsig.o $(LDFLAGS) $(LIBS)
+sshsigopt_fuzz: sshsigopt_fuzz.o $(COMMON_OBJS)
+	$(CXX) -o $@ sshsigopt_fuzz.o $(COMMON_OBJS) ../../../sshsig.o $(LDFLAGS) $(LIBS)
 
-privkey_fuzz: privkey_fuzz.o
-	$(CXX) -o $@ privkey_fuzz.o $(LDFLAGS) $(LIBS)
+privkey_fuzz: privkey_fuzz.o $(COMMON_OBJS)
+	$(CXX) -o $@ privkey_fuzz.o $(COMMON_OBJS) $(LDFLAGS) $(LIBS)
 
 clean:
 	-rm -f *.o $(TARGETS)
diff --git a/regress/misc/fuzz-harness/ssh-sk-null.cc b/regress/misc/fuzz-harness/ssh-sk-null.cc
index de9a889f9..199af1121 100644
--- a/regress/misc/fuzz-harness/ssh-sk-null.cc
+++ b/regress/misc/fuzz-harness/ssh-sk-null.cc
@@ -25,7 +25,16 @@ extern "C" {
 #include "ssh-sk.h"
 
 int
-sshsk_sign(const char *provider, struct sshkey *key,
+sshsk_enroll(int type, const char *provider_path, const char *device,
+    const char *application, const char *userid, uint8_t flags,
+    const char *pin, struct sshbuf *challenge_buf,
+    struct sshkey **keyp, struct sshbuf *attest)
+{
+	return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+int
+sshsk_sign(const char *provider_path, struct sshkey *key,
     u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,
     u_int compat, const char *pin)
 {
@@ -33,16 +42,8 @@ sshsk_sign(const char *provider, struct sshkey *key,
 }
 
 int
-sshsk_enroll(int type, const char *provider_path, const char *application,
-    uint8_t flags, const char *pin, struct sshbuf *challenge_buf,
-    struct sshkey **keyp, struct sshbuf *attest)
-{
-	return SSH_ERR_FEATURE_UNSUPPORTED;
-}
-
-int
-sshsk_load_resident(const char *provider_path, const char *pin,
-    struct sshkey ***keysp, size_t *nkeysp)
+sshsk_load_resident(const char *provider_path, const char *device,
+    const char *pin, struct sshkey ***keysp, size_t *nkeysp)
 {
 	return SSH_ERR_FEATURE_UNSUPPORTED;
 }