diff --git a/libraries/AP_HAL_PX4/I2CDevice.cpp b/libraries/AP_HAL_PX4/I2CDevice.cpp
index 34a9ed161a..07487ea2f4 100644
--- a/libraries/AP_HAL_PX4/I2CDevice.cpp
+++ b/libraries/AP_HAL_PX4/I2CDevice.cpp
@@ -23,6 +23,8 @@ namespace PX4 {
 
 uint8_t PX4::PX4_I2C::instance;
 
+DeviceBus I2CDevice::businfo[I2CDevice::num_buses];
+
 /*
   constructor for I2C wrapper class
  */    
diff --git a/libraries/AP_HAL_PX4/I2CDevice.h b/libraries/AP_HAL_PX4/I2CDevice.h
index fd3da9660f..11f9ecf466 100644
--- a/libraries/AP_HAL_PX4/I2CDevice.h
+++ b/libraries/AP_HAL_PX4/I2CDevice.h
@@ -67,7 +67,7 @@ public:
 
 private:
     static const uint8_t num_buses = 2;
-    DeviceBus businfo[num_buses];
+    static DeviceBus businfo[num_buses];
     
     uint8_t _busnum;
     PX4_I2C _px4dev;