diff --git a/lib/libc/aarch64/string/Makefile.inc b/lib/libc/aarch64/string/Makefile.inc
index 876ef4257b4c..f8c67319fe12 100644
--- a/lib/libc/aarch64/string/Makefile.inc
+++ b/lib/libc/aarch64/string/Makefile.inc
@@ -1,51 +1,52 @@
 #
 # String handling from the Arm Optimized Routines
 # https://github.com/ARM-software/optimized-routines
 #
 
 AARCH64_STRING_FUNCS= \
 	memchr \
 	memcmp \
 	memcpy \
 	memmove \
 	memrchr \
 	memset \
 	stpcpy \
 	strchr \
 	strchrnul \
 	strcpy \
 	strlen \
 	strnlen \
 	strrchr
 
 # SIMD-enhanced routines not derived from Arm's code
 MDSRCS+= \
 	strcmp.S \
 	strspn.S \
 	strcspn.S \
 	strpbrk.c \
 	strsep.c \
 	strcat.c \
 	strlcpy.S \
 	strncmp.S \
 	memccpy.S \
-	strncat.c
+	strncat.c \
+	strlcat.c
 
 #
 # Add the above functions. Generate an asm file that includes the needed
 # Arm Optimized Routines file defining the function name to the libc name.
 # Some file need multiple macros defined or a weak symbol added we can
 # override the generated file in these cases.
 #
 .for FUNC in ${AARCH64_STRING_FUNCS}
 .if !exists(${FUNC}.S)
 ${FUNC}.S:
 	printf '/* %sgenerated by libc/aarch64/string/Makefile.inc */\n' @ > ${.TARGET}
 	printf '#define	__%s_aarch64 %s\n' ${FUNC} ${FUNC} >> ${.TARGET}
 	printf '#include "aarch64/%s.S"\n' ${FUNC} >> ${.TARGET}
 CLEANFILES+=	${FUNC}.S
 .endif
 
 MDSRCS+=	${FUNC}.S
 CFLAGS.${FUNC}.S+=-I${SRCTOP}/contrib/arm-optimized-routines/string
 .endfor
diff --git a/lib/libc/aarch64/string/memchr.S b/lib/libc/aarch64/string/memchr.S
new file mode 100644
index 000000000000..6d4330d9115e
--- /dev/null
+++ b/lib/libc/aarch64/string/memchr.S
@@ -0,0 +1,4 @@
+	.weak memchr
+	.set memchr, __memchr_aarch64
+
+#include "aarch64/memchr.S"
diff --git a/lib/libc/aarch64/string/strlcat.c b/lib/libc/aarch64/string/strlcat.c
new file mode 100644
index 000000000000..c3c996163ade
--- /dev/null
+++ b/lib/libc/aarch64/string/strlcat.c
@@ -0,0 +1,25 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Robert Clausecker
+ */
+
+#include <sys/cdefs.h>
+
+#include <string.h>
+
+void *__memchr_aarch64(const void *, int, size_t);
+size_t __strlcpy(char *restrict, const char *restrict, size_t);
+
+size_t
+strlcat(char *restrict dst, const char *restrict src, size_t dstsize)
+{
+	char *loc = __memchr_aarch64(dst, '\0', dstsize);
+
+	if (loc != NULL) {
+		size_t dstlen = (size_t)(loc - dst);
+
+		return (dstlen + __strlcpy(loc, src, dstsize - dstlen));
+	} else
+		return (dstsize + strlen(src));
+}