diff --git a/rpio.go b/rpio.go
index 44e2b3a..f2c9655 100644
--- a/rpio.go
+++ b/rpio.go
@@ -304,6 +304,5 @@ func Open() (err error) {
 func Close() {
 	memlock.Lock()
 	syscall.Munmap(mem8)
-	syscall.Munmap(mem)
 	memlock.Unlock()
 }