diff --git a/rpio.go b/rpio.go
index 557e993..21ce563 100644
--- a/rpio.go
+++ b/rpio.go
@@ -744,7 +744,7 @@ func Open() (err error) {
 
 	// Open fd for rw mem access; try dev/mem first (need root)
 	file, err = os.OpenFile("/dev/mem", os.O_RDWR|os.O_SYNC, os.ModePerm)
-	if os.IsPermission(err) { // try gpiomem otherwise (some extra functions like clock and pwm setting wont work)
+	if os.IsNotExist(err) || os.IsPermission(err) { // try gpiomem otherwise (some extra functions like clock and pwm setting wont work)
 		file, err = os.OpenFile("/dev/gpiomem", os.O_RDWR|os.O_SYNC, os.ModePerm)
 	}
 	if err != nil {