diff --git a/mdassemble.c b/mdassemble.c
index 78d363a..471ffeb 100644
--- a/mdassemble.c
+++ b/mdassemble.c
@@ -32,7 +32,7 @@ char const Name[] = "mdassemble";
 /* from mdopen.c */
 int open_mddev(char *dev, int report_errors/*unused*/)
 {
-	int mdfd = open(dev, O_RDWR);
+	int mdfd = open(dev, O_RDONLY);
 	if (mdfd < 0)
 		pr_err("error opening %s: %s\n",
 			dev, strerror(errno));
diff --git a/mdopen.c b/mdopen.c
index 0ea3874..685ca32 100644
--- a/mdopen.c
+++ b/mdopen.c
@@ -416,9 +416,7 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy,
  */
 int open_mddev(char *dev, int report_errors)
 {
-	int mdfd = open(dev, O_RDWR);
-	if (mdfd < 0 && errno == EACCES)
-		mdfd = open(dev, O_RDONLY);
+	int mdfd = open(dev, O_RDONLY);
 	if (mdfd < 0) {
 		if (report_errors)
 			pr_err("error opening %s: %s\n",