--- a/devtools/shared/adb/adb-device.js
+++ b/devtools/shared/adb/adb-device.js
@@ -23,17 +23,17 @@ Device.prototype = {
   pull: ADB.pull.bind(ADB),
   reboot: ADB.reboot.bind(ADB),
   rebootRecovery: ADB.rebootRecovery.bind(ADB),
   rebootBootloader: ADB.rebootBootloader.bind(ADB),
 
   isRoot() {
     return ADB.shell("id").then(stdout => {
       if (stdout) {
-        let uid = stdout.match(/uid=(\d+)/)[1];
+        const uid = stdout.match(/uid=(\d+)/)[1];
         return uid == "0";
       }
       return false;
     });
   },
 
   summonRoot() {
     return ADB.root();