diff --git a/include/cutils/android_reboot.h b/include/cutils/android_reboot.h
index 8c30e8e..85e1b7e 100644
--- a/include/cutils/android_reboot.h
+++ b/include/cutils/android_reboot.h
@@ -27,7 +27,7 @@
 /* Properties */
 #define ANDROID_RB_PROPERTY "sys.powerctl"
 
-int android_reboot(int cmd, int flags, char *arg);
+int android_reboot(int cmd, int flags, const char *arg);
 
 __END_DECLS
 
diff --git a/libcutils/android_reboot.c b/libcutils/android_reboot.c
index aa86206..6ae23c1 100644
--- a/libcutils/android_reboot.c
+++ b/libcutils/android_reboot.c
@@ -89,7 +89,7 @@
 }
 
 
-int android_reboot(int cmd, int flags UNUSED, char *arg)
+int android_reboot(int cmd, int flags UNUSED, const char *arg)
 {
     int ret;