Index: head/sys/dev/acpica/acpi.c
===================================================================
--- head/sys/dev/acpica/acpi.c
+++ head/sys/dev/acpica/acpi.c
@@ -866,7 +866,7 @@
                 strlcat(buf, buf2, buflen);
         }
     } else {
-        snprintf(buf, buflen, "unknown");
+        snprintf(buf, buflen, "");
     }
     return (0);
 }
Index: head/sys/dev/nvdimm/nvdimm.c
===================================================================
--- head/sys/dev/nvdimm/nvdimm.c
+++ head/sys/dev/nvdimm/nvdimm.c
@@ -571,7 +571,7 @@
 	if (handle != NULL)
 		res = snprintf(buf, buflen, "handle=%s", acpi_name(handle));
 	else
-		res = snprintf(buf, buflen, "unknown");
+		res = snprintf(buf, buflen, "");
 
 	if (res >= buflen)
 		return (EOVERFLOW);