diff --git a/ion/src/device/shared/drivers/board.cpp b/ion/src/device/shared/drivers/board.cpp
index de6ef6442..2b17cbd9b 100644
--- a/ion/src/device/shared/drivers/board.cpp
+++ b/ion/src/device/shared/drivers/board.cpp
@@ -58,7 +58,7 @@ void shutdownPeripherals(bool keepLEDAwake) {
   Display::shutdown();
 }
 
-Frequency sStandardFrequency = Frequency::High;
+static Frequency sStandardFrequency = Frequency::High;
 
 Frequency standardFrequency() {
   return sStandardFrequency;