diff --git a/Marlin/src/HAL/HAL_AVR/MarlinSerial.cpp b/Marlin/src/HAL/HAL_AVR/MarlinSerial.cpp
index ea5c489f65..36134f7b89 100644
--- a/Marlin/src/HAL/HAL_AVR/MarlinSerial.cpp
+++ b/Marlin/src/HAL/HAL_AVR/MarlinSerial.cpp
@@ -43,7 +43,7 @@
   #include "MarlinSerial.h"
   #include "../../Marlin.h"
 
-  template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_r MarlinSerial<Cfg>::rx_buffer = { 0 };
+  template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_r MarlinSerial<Cfg>::rx_buffer = { 0, 0, { 0 } };
   template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_t MarlinSerial<Cfg>::tx_buffer = { 0 };
   template<typename Cfg> bool     MarlinSerial<Cfg>::_written = false;
   template<typename Cfg> uint8_t  MarlinSerial<Cfg>::xon_xoff_state = MarlinSerial<Cfg>::XON_XOFF_CHAR_SENT | MarlinSerial<Cfg>::XON_CHAR;
diff --git a/Marlin/src/HAL/HAL_DUE/MarlinSerial_Due.cpp b/Marlin/src/HAL/HAL_DUE/MarlinSerial_Due.cpp
index cbcd9dcd3f..ef72c38270 100644
--- a/Marlin/src/HAL/HAL_DUE/MarlinSerial_Due.cpp
+++ b/Marlin/src/HAL/HAL_DUE/MarlinSerial_Due.cpp
@@ -33,7 +33,7 @@
 #include "InterruptVectors_Due.h"
 #include "../../Marlin.h"
 
-template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_r MarlinSerial<Cfg>::rx_buffer = { 0 };
+template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_r MarlinSerial<Cfg>::rx_buffer = { 0, 0, { 0 } };
 template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_t MarlinSerial<Cfg>::tx_buffer = { 0 };
 template<typename Cfg> bool     MarlinSerial<Cfg>::_written = false;
 template<typename Cfg> uint8_t  MarlinSerial<Cfg>::xon_xoff_state = MarlinSerial<Cfg>::XON_XOFF_CHAR_SENT | MarlinSerial<Cfg>::XON_CHAR;
diff --git a/Marlin/src/HAL/shared/Delay.h b/Marlin/src/HAL/shared/Delay.h
index 04771a2e03..4cdd479210 100644
--- a/Marlin/src/HAL/shared/Delay.h
+++ b/Marlin/src/HAL/shared/Delay.h
@@ -140,9 +140,9 @@
 #endif
 
 // Delay in nanoseconds
-#define DELAY_NS(x) DELAY_CYCLES( (x) * (F_CPU/1000000L) / 1000L )
+#define DELAY_NS(x) DELAY_CYCLES( (x) * (F_CPU / 1000000UL) / 1000UL )
 
 // Delay in microseconds
-#define DELAY_US(x) DELAY_CYCLES( (x) * (F_CPU/1000000L) )
+#define DELAY_US(x) DELAY_CYCLES( (x) * (F_CPU / 1000000UL) )
 
 #endif // MARLIN_DELAY_H
diff --git a/Marlin/src/core/macros.h b/Marlin/src/core/macros.h
index 294d6213ca..945e983e97 100644
--- a/Marlin/src/core/macros.h
+++ b/Marlin/src/core/macros.h
@@ -49,7 +49,7 @@
 
 // Clock speed factors
 #if !defined(CYCLES_PER_MICROSECOND) && !defined(__STM32F1__)
-  #define CYCLES_PER_MICROSECOND (F_CPU / 1000000L) // 16 or 20 on AVR
+  #define CYCLES_PER_MICROSECOND (F_CPU / 1000000UL) // 16 or 20 on AVR
 #endif
 
 // Nanoseconds per cycle
diff --git a/Marlin/src/module/configuration_store.cpp b/Marlin/src/module/configuration_store.cpp
index 66e65478c1..2e34fb3028 100644
--- a/Marlin/src/module/configuration_store.cpp
+++ b/Marlin/src/module/configuration_store.cpp
@@ -927,7 +927,7 @@ void MarlinSettings::postprocess() {
     //
     {
       #if DISABLED(ADVANCED_PAUSE_FEATURE)
-        const fil_change_settings_t fc_settings[EXTRUDERS] = { { 0 } };
+        const fil_change_settings_t fc_settings[EXTRUDERS] = { 0, 0 };
       #endif
       _FIELD_TEST(fc_settings);
       EEPROM_WRITE(fc_settings);