diff --git a/libs/color-sensor/color.ts b/libs/color-sensor/color.ts
index 72121eb0..e6d977df 100644
--- a/libs/color-sensor/color.ts
+++ b/libs/color-sensor/color.ts
@@ -1,5 +1,5 @@
 const enum ColorSensorMode {
-    None = -1,
+    None = 0,
     //% block="reflected light intensity"
     ReflectedLightIntensity = 0,
     //% block="ambient light intensity"
diff --git a/libs/core/input.ts b/libs/core/input.ts
index 27d3c160..8065b682 100644
--- a/libs/core/input.ts
+++ b/libs/core/input.ts
@@ -212,7 +212,6 @@ namespace sensors.internal {
 
         _activated() {
             this.realmode = 0
-            // uartReset(this.port) // TODO is it ever needed?
             this._setMode(this.mode)
         }
 
diff --git a/libs/gyro-sensor/gyro.ts b/libs/gyro-sensor/gyro.ts
index 3b8b9f3c..1200307d 100644
--- a/libs/gyro-sensor/gyro.ts
+++ b/libs/gyro-sensor/gyro.ts
@@ -1,5 +1,5 @@
 const enum GyroSensorMode {
-    None = -1,
+    None = 0,
     Angle = 0,
     Rate = 1,
 }
diff --git a/libs/infrared-sensor/ir.ts b/libs/infrared-sensor/ir.ts
index 11ffd744..85866fd0 100644
--- a/libs/infrared-sensor/ir.ts
+++ b/libs/infrared-sensor/ir.ts
@@ -1,5 +1,5 @@
 const enum InfraredSensorMode {
-    None = -1,
+    None = 0,
     Proximity = 0,
     Seek = 1,
     RemoteControl = 2,