diff --git a/cores/esp8266/core_esp8266_main.cpp b/cores/esp8266/core_esp8266_main.cpp
index ad13347154..ff95d08cfb 100644
--- a/cores/esp8266/core_esp8266_main.cpp
+++ b/cores/esp8266/core_esp8266_main.cpp
@@ -69,7 +69,7 @@ static uint32_t s_cycles_at_yield_start;
  */
 #define ETS_INTR_LOCK_NEST_MAX 7
 static uint16_t ets_intr_lock_stack[ETS_INTR_LOCK_NEST_MAX];
-static byte     ets_intr_lock_stack_ptr=0;
+static uint8_t  ets_intr_lock_stack_ptr=0;
 
 
 extern "C" {
diff --git a/libraries/ESP8266WiFiMesh/src/TypeConversionFunctions.cpp b/libraries/ESP8266WiFiMesh/src/TypeConversionFunctions.cpp
index cfcd8f6aed..7e4b8c3419 100644
--- a/libraries/ESP8266WiFiMesh/src/TypeConversionFunctions.cpp
+++ b/libraries/ESP8266WiFiMesh/src/TypeConversionFunctions.cpp
@@ -33,7 +33,7 @@ using namespace experimental::TypeConversion;
 
 namespace MeshTypeConversionFunctions 
 {
-  String uint64ToString(uint64_t number, const byte base)
+  String uint64ToString(uint64_t number, const uint8_t base)
   {
     assert(2 <= base && base <= 36);
     
@@ -59,7 +59,7 @@ namespace MeshTypeConversionFunctions
     return result;
   }
   
-  uint64_t stringToUint64(const String &string, const byte base)
+  uint64_t stringToUint64(const String &string, const uint8_t base)
   {
     assert(2 <= base && base <= 36);