diff --git a/emulators/virtualbox-ose/Makefile b/emulators/virtualbox-ose/Makefile
--- a/emulators/virtualbox-ose/Makefile
+++ b/emulators/virtualbox-ose/Makefile
@@ -211,10 +211,16 @@
 
 .include <bsd.port.pre.mk>
 
+.if ${OPSYS} == FreeBSD && \
+    (${OSVERSION} < 1300513 || ${OSVERSION} >= 1400000 && ${OSVERSION} < 1400026)
+EXTRA_PATCHES+=	${PATCHDIR}/extrapatch-src_VBox_Devices_PC_DevFwCommon.cpp
+.endif
+
 .if ${CHOSEN_COMPILER_TYPE} == clang
 # llvm10 in FreeBSD before r364284 miscompiles virtualbox 6.1 causing errors.
 # force llvm11 from ports
-.if ${OPSYS} == FreeBSD && ${OSVERSION} < 1300109
+.if ${OPSYS} == FreeBSD && \
+    (${OSVERSION} < 1203502 || ${OSVERSION} >= 1300000 && ${OSVERSION} < 1300109)
 BUILD_DEPENDS+=	clang${VBOX_LLVM_VER}:devel/llvm${VBOX_LLVM_VER}
 CC=		clang${VBOX_LLVM_VER}
 CXX=		clang++${VBOX_LLVM_VER}
diff --git a/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_DevFwCommon.cpp b/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_DevFwCommon.cpp
new file mode 100644
--- /dev/null
+++ b/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_DevFwCommon.cpp
@@ -0,0 +1,14 @@
+--- src/VBox/Devices/PC/DevFwCommon.cpp.orig
++++ src/VBox/Devices/PC/DevFwCommon.cpp
+@@ -40,6 +40,11 @@
+ #include "VBoxDD2.h"
+ #include "DevFwCommon.h"
+ 
++static inline void *
++mempcpy(void *__restrict dst, const void *__restrict src, size_t len)
++{
++	return ((char *)memcpy(dst, src, len) + len);
++}
+ 
+ /*********************************************************************************************************************************
+ *   Defined Constants And Macros                                                                                                 *