diff --git a/sys/dev/ofw/ofw_fdt.c b/sys/dev/ofw/ofw_fdt.c
--- a/sys/dev/ofw/ofw_fdt.c
+++ b/sys/dev/ofw/ofw_fdt.c
@@ -32,6 +32,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/ctype.h>
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/systm.h>
@@ -107,11 +108,13 @@
 #define	FDT_FBSDVER_LEN	16
 #define	FDT_MODEL_LEN	80
 #define	FDT_COMPAT_LEN	255
+#define	FDT_SERIAL_LEN	32
 
 static void *fdtp = NULL;
 static char fdt_model[FDT_MODEL_LEN];
 static char fdt_compatible[FDT_COMPAT_LEN];
 static char fdt_fbsd_version[FDT_FBSDVER_LEN];
+static char fdt_serial[FDT_SERIAL_LEN];
 
 static int
 sysctl_handle_dtb(SYSCTL_HANDLER_ARGS)
@@ -143,6 +146,10 @@
 		SYSCTL_ADD_STRING(NULL, SYSCTL_STATIC_CHILDREN(_hw_fdt),
 		    OID_AUTO, "freebsd-version", CTLFLAG_RD, fdt_fbsd_version,
 		    FDT_FBSDVER_LEN, "FreeBSD DTS branding version");
+	if (fdt_serial[0] != '\0')
+		SYSCTL_ADD_STRING(NULL, SYSCTL_STATIC_CHILDREN(_hw_fdt),
+		    OID_AUTO, "serial-number", CTLFLAG_RD, fdt_serial,
+		    FDT_SERIAL_LEN, "Serial number");
 }
 SYSINIT(dtb_oid, SI_SUB_KMEM, SI_ORDER_ANY, sysctl_register_fdt_oid, NULL);
 
@@ -161,20 +168,44 @@
 	fdtp = data;
 	root = ofw_fdt_finddevice(NULL, "/");
 	len = ofw_fdt_getproplen(NULL, root, "model");
-	bzero(fdt_model, FDT_MODEL_LEN);
-	ofw_fdt_getprop(NULL, root, "model", fdt_model, FDT_MODEL_LEN);
+	if (len > 0 && len <= FDT_MODEL_LEN) {
+		bzero(fdt_model, FDT_MODEL_LEN);
+		ofw_fdt_getprop(NULL, root, "model", fdt_model, FDT_MODEL_LEN);
+	}
 	len = ofw_fdt_getproplen(NULL, root, "compatible");
-	bzero(fdt_compatible, FDT_COMPAT_LEN);
-	ofw_fdt_getprop(NULL, root, "compatible", fdt_compatible, FDT_COMPAT_LEN);
-	/* Replace the middle '\0' with ' ' */
-	for (i = 0; i < len - 1; i++)
-		if (fdt_compatible[i] == '\0')
-			fdt_compatible[i] = ' ';
-	if ((len = ofw_fdt_getproplen(NULL, root, "freebsd,dts-version")) > 0) {
+	if (len > 0 && len <= FDT_COMPAT_LEN) {
+		bzero(fdt_compatible, FDT_COMPAT_LEN);
+		ofw_fdt_getprop(NULL, root, "compatible", fdt_compatible,
+		    FDT_COMPAT_LEN);
+		/* Replace the middle '\0' with ' ' */
+		for (i = 0; i < len - 1; i++)
+			if (fdt_compatible[i] == '\0')
+				fdt_compatible[i] = ' ';
+	}
+	len = ofw_fdt_getproplen(NULL, root, "freebsd,dts-version");
+	if (len > 0 && len <= FDT_FBSDVER_LEN) {
 		bzero(fdt_fbsd_version, FDT_FBSDVER_LEN);
 		ofw_fdt_getprop(NULL, root, "freebsd,dts-version",
 		  fdt_fbsd_version, FDT_FBSDVER_LEN);
 	}
+	len = ofw_fdt_getproplen(NULL, root, "serial-number");
+	if (len > 0 && len <= FDT_SERIAL_LEN) {
+		bzero(fdt_serial, FDT_SERIAL_LEN);
+		ofw_fdt_getprop(NULL, root, "serial-number",
+		    fdt_serial, FDT_SERIAL_LEN);
+		/*
+		 * Non-standard property; check for NUL-terminated
+		 * printable string.
+		 */
+		for (i = 0; i < len - 1; i++) {
+			if (!isprint(fdt_serial[i])) {
+				fdt_serial[0] = '\0';
+				break;
+			}
+		}
+		if (fdt_serial[len - 1] != '\0')
+			fdt_serial[0] = '\0';
+	}
 	return (0);
 }