diff --git a/cubesatsim/cubesatsim.ino b/cubesatsim/cubesatsim.ino
index 0b793655..3f63b05d 100644
--- a/cubesatsim/cubesatsim.ino
+++ b/cubesatsim/cubesatsim.ino
@@ -59,7 +59,7 @@ WiFiClient client;
 //#define PICO_W    // define if Pico W board.  Otherwise, compilation fail for Pico or runtime fail if compile as Pico W
 #define PICO_0V1 // define for Pico v0.1 hardware
 
-#ifdef PICO_0v1
+#ifdef PICO_0V1
 #define BPF_PIN 8  // BPF is installed for v0.1 Pico
 #define PI_3V3_PIN 9  // 3.3V supply used to detect Pi Zero for v0.1 Pico
 #endif