diff --git a/libraries/Desktop/support/DataFlash_APM1.cpp b/libraries/Desktop/support/DataFlash_APM1.cpp
index 1fb7b5a608a71ad2219a262a4bd523c1f78c10ce..36e2dad8fa5a83b6805600bfd0a103463a691e91 100644
--- a/libraries/Desktop/support/DataFlash_APM1.cpp
+++ b/libraries/Desktop/support/DataFlash_APM1.cpp
@@ -123,4 +123,4 @@ void DataFlash_APM1::ChipErase(void (*delay_cb)(unsigned long))
 }
 
 // make one instance for the user to use
-DataFlash_APM1::DataFlash_APM1() {}
+DataFlash_APM1::DataFlash_APM1(AP_Semaphore* spi_semaphore) {}