diff --git a/geo_lookup/geo_mag_declination.cpp b/geo_lookup/geo_mag_declination.cpp
index 8f329f6c12..5ce4760966 100644
--- a/geo_lookup/geo_mag_declination.cpp
+++ b/geo_lookup/geo_mag_declination.cpp
@@ -46,10 +46,10 @@
 
 #include <mathlib/mathlib.h>
 
+#include <math.h>
 #include <stdint.h>
 
 using math::constrain;
-using math::floorf;
 
 /** set this always to the sampling in degrees for the table below */
 static constexpr float SAMPLING_RES = 10.0f;
diff --git a/mathlib/mathlib.cpp b/mathlib/mathlib.cpp
index ca34a5569c..69aee15ffc 100644
--- a/mathlib/mathlib.cpp
+++ b/mathlib/mathlib.cpp
@@ -70,16 +70,6 @@ float degrees(float radians)
 	return (radians * 180.0f) / M_PI_F;
 }
 
-int floorf(float input)
-{
-	int res = int(input);
-	if (res > input) {
-		res--;
-	}
-
-	return res;
-}
-
 } // namespace math
 
 #endif /* ECL_STANDALONE */
diff --git a/mathlib/mathlib.h b/mathlib/mathlib.h
index e22a8ee508..04a1803257 100644
--- a/mathlib/mathlib.h
+++ b/mathlib/mathlib.h
@@ -60,7 +60,6 @@ float max(float val1, float val2);
 float constrain(float val, float min, float max);
 float radians(float degrees);
 float degrees(float radians);
-int floorf(float input);
 
 }
 #else