diff --git a/firmware/pch/pch.h b/firmware/pch/pch.h
index 8430000186..a1e4f698bb 100644
--- a/firmware/pch/pch.h
+++ b/firmware/pch/pch.h
@@ -40,7 +40,7 @@
 #include "allsensors.h"
 #include "sensor.h"
 #include "settings.h"
-#include "interpolation.h"
+#include "efi_interpolation.h"
 #include "perf_trace.h"
 #include "hardware.h"
 #include "thread_priority.h"
diff --git a/firmware/util/containers/table_helper.h b/firmware/util/containers/table_helper.h
index b360f8ca93..f517e55da3 100644
--- a/firmware/util/containers/table_helper.h
+++ b/firmware/util/containers/table_helper.h
@@ -8,7 +8,7 @@
 #pragma once
 
 #include <math.h>
-#include "interpolation.h"
+#include "efi_interpolation.h"
 #include "efilib.h"
 #include "efi_ratio.h"
 #include "scaled_channel.h"
diff --git a/firmware/util/math/interpolation.h b/firmware/util/math/efi_interpolation.h
similarity index 97%
rename from firmware/util/math/interpolation.h
rename to firmware/util/math/efi_interpolation.h
index 3672df938c..2505cf70ec 100644
--- a/firmware/util/math/interpolation.h
+++ b/firmware/util/math/efi_interpolation.h
@@ -1,5 +1,6 @@
 /**
- * @file    interpolation.h
+ * @file    efi_interpolation.h
+ * See also libfirmware interpolation.h
  *
  * @date Oct 17, 2013
  * @author Andrey Belomutskiy, (c) 2012-2020
@@ -7,6 +8,7 @@
 
 #pragma once
 
+#include <rusefi/isnan.h>
 #include <math.h>
 #include "datalogging.h"
 #include "obd_error_codes.h"
diff --git a/firmware/util/math/interpolation.cpp b/firmware/util/math/interpolation.cpp
index d38df3bbaa..302836bea8 100644
--- a/firmware/util/math/interpolation.cpp
+++ b/firmware/util/math/interpolation.cpp
@@ -12,7 +12,7 @@
 
 #include "pch.h"
 
-#include "interpolation.h"
+#include "efi_interpolation.h"
 
 #define BINARY_PERF true
 
diff --git a/unit_tests/test_basic_math/test_find_index.cpp b/unit_tests/test_basic_math/test_find_index.cpp
index ca4d9f6801..e248d0541e 100644
--- a/unit_tests/test_basic_math/test_find_index.cpp
+++ b/unit_tests/test_basic_math/test_find_index.cpp
@@ -6,7 +6,7 @@
  */
 
 #include "pch.h"
-#include "interpolation.h"
+#include "efi_interpolation.h"
 
 static void testIndex(const int expected, const float array[], int size, float value) {
 	ASSERT_EQ(expected, findIndex(array, size, value));
diff --git a/unit_tests/test_basic_math/test_interpolation_3d.cpp b/unit_tests/test_basic_math/test_interpolation_3d.cpp
index 78ee6b0467..850538e4b2 100644
--- a/unit_tests/test_basic_math/test_interpolation_3d.cpp
+++ b/unit_tests/test_basic_math/test_interpolation_3d.cpp
@@ -9,7 +9,7 @@
 
 #include <stdlib.h>
 
-#include "interpolation.h"
+#include "efi_interpolation.h"
 
 float rpmBins[5] = { 100, 200, 300, 400, 500 };
 scaled_channel<uint8_t, 1, 50> rpmBinsScaledByte[5] = { 100, 200, 300, 400, 500};