diff --git a/firmware/controllers/sensors/allsensors.h b/firmware/controllers/sensors/allsensors.h
index 043a30d461..e5a40a8496 100644
--- a/firmware/controllers/sensors/allsensors.h
+++ b/firmware/controllers/sensors/allsensors.h
@@ -23,7 +23,7 @@
 #include "adc_inputs.h"
 
 #if EFI_PROD_CODE || EFI_SIMULATOR
-#include "adc_math.h"
+#include "adc_inputs.h"
 #endif
 
 void initSensors(Logging *sharedLogger DECLARE_ENGINE_PARAMETER_SUFFIX);
diff --git a/firmware/development/engine_sniffer.cpp b/firmware/development/engine_sniffer.cpp
index dbbf588a6f..c60df40be3 100644
--- a/firmware/development/engine_sniffer.cpp
+++ b/firmware/development/engine_sniffer.cpp
@@ -26,7 +26,7 @@
 
 #include "main.h"
 #include "engine_sniffer.h"
-#include "adc_math.h"
+#include "adc_inputs.h"
 
 #if EFI_ENGINE_SNIFFER || defined(__DOXYGEN__)
 
diff --git a/firmware/hw_layer/adc_external.h b/firmware/hw_layer/adc_external.h
index a3b9399a3c..808c0e106f 100644
--- a/firmware/hw_layer/adc_external.h
+++ b/firmware/hw_layer/adc_external.h
@@ -1,6 +1,7 @@
 /*
  * @file    adc_external.h
  *
+ * external ADC is probably broken, at least there is a major mess
  *
  * @date Aug 18, 2013
  * @author Andrey Belomutskiy, (c) 2012-2017
diff --git a/firmware/hw_layer/adc_inputs.h b/firmware/hw_layer/adc_inputs.h
index f25c2b15c8..df7597adb9 100644
--- a/firmware/hw_layer/adc_inputs.h
+++ b/firmware/hw_layer/adc_inputs.h
@@ -1,6 +1,6 @@
 /**
  * @file	adc_inputs.h
- * @brief	Low level ADC code
+ * @brief	Low level internal ADC code
  *
  * @date Jan 14, 2013
  * @author Andrey Belomutskiy, (c) 2012-2017
@@ -10,9 +10,9 @@
 #define ADC_INPUTS_H_
 
 #include "main.h"
-#include "adc_math.h"
 
 #if HAL_USE_ADC || defined(__DOXYGEN__)
+#include "adc_math.h"
 
 const char * getAdcMode(adc_channel_e hwChannel);
 void initAdcInputs(bool boardTestMode);
diff --git a/firmware/hw_layer/algo/adc_math.h b/firmware/hw_layer/algo/adc_math.h
index 1d85b6e866..a4abd27d1e 100644
--- a/firmware/hw_layer/algo/adc_math.h
+++ b/firmware/hw_layer/algo/adc_math.h
@@ -1,6 +1,8 @@
 /**
  * @file	adc_math.h
  *
+ * todo: all this looks to be about internal ADC, merge this file with
+ *
  * @date Mar 18, 2014
  * @author Andrey Belomutskiy, (c) 2012-2017
  */