diff --git a/RNode_Firmware.ino b/RNode_Firmware.ino
index 0bf649a..07a5cea 100644
--- a/RNode_Firmware.ino
+++ b/RNode_Firmware.ino
@@ -443,7 +443,9 @@ void update_airtime() {
     }
     longterm_channel_util = (float)longterm_channel_util_sum/(float)AIRTIME_BINS;
 
-    update_csma_p();
+    #if MCU_VARIANT == MCU_ESP32
+      update_csma_p();
+    #endif
     kiss_indicate_channel_stats();
   #endif
 }
@@ -1097,12 +1099,14 @@ void validate_status() {
   }
 }
 
-#define _e 2.71828183
-#define _S 10.0
-float csma_slope(float u) { return (pow(_e,_S*u-_S/2.0))/(pow(_e,_S*u-_S/2.0)+1.0); }
-void update_csma_p() {
-  csma_p = (uint8_t)((1.0-(csma_p_min+(csma_p_max-csma_p_min)*csma_slope(airtime)))*255.0);
+#if MCU_VARIANT == MCU_ESP32
+  #define _e 2.71828183
+  #define _S 10.0
+  float csma_slope(float u) { return (pow(_e,_S*u-_S/2.0))/(pow(_e,_S*u-_S/2.0)+1.0); }
+  void update_csma_p() {
+      csma_p = (uint8_t)((1.0-(csma_p_min+(csma_p_max-csma_p_min)*csma_slope(airtime)))*255.0);
 }
+#endif
 
 void loop() {
   if (radio_online) {
diff --git a/Release/console_image.bin b/Release/console_image.bin
index 9321c0e..8d66a04 100644
Binary files a/Release/console_image.bin and b/Release/console_image.bin differ