diff --git a/Marlin/src/HAL/LPC1768/HAL.cpp b/Marlin/src/HAL/LPC1768/HAL.cpp
index f0559d268a1caf263d16c01eaf278f592547a728..f206ce7adb76fe3b047ccf492556243803e3beaf 100644
--- a/Marlin/src/HAL/LPC1768/HAL.cpp
+++ b/Marlin/src/HAL/LPC1768/HAL.cpp
@@ -67,9 +67,7 @@ int16_t PARSED_PIN_INDEX(const char code, const int16_t dval) {
   return ind > -1 ? ind : dval;
 }
 
-void flashFirmware(int16_t value) {
-  NVIC_SystemReset();
-}
+void flashFirmware(const int16_t) { NVIC_SystemReset(); }
 
 void HAL_clear_reset_source(void) {
   #if ENABLED(USE_WATCHDOG)
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index c727877ff37261d910e9a64c2dd3a144e20da8fa..f5ea629f169480aeac2b2a2a39f04d76c7283bf6 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -195,7 +195,7 @@ int16_t PARSED_PIN_INDEX(const char code, const int16_t dval);
 void HAL_idletask();
 
 #define PLATFORM_M997_SUPPORT
-void flashFirmware(int16_t value);
+void flashFirmware(const int16_t);
 
 /**
  * set_pwm_frequency
diff --git a/Marlin/src/HAL/STM32/HAL.cpp b/Marlin/src/HAL/STM32/HAL.cpp
index 5d8c686af30eeb7f911f4c29c9c9f148e8ed4c6e..77f8d2764055308c2b4cc900ca9b7be27b0ddf3c 100644
--- a/Marlin/src/HAL/STM32/HAL.cpp
+++ b/Marlin/src/HAL/STM32/HAL.cpp
@@ -133,6 +133,6 @@ void HAL_adc_start_conversion(const uint8_t adc_pin) { HAL_adc_result = analogRe
 
 uint16_t HAL_adc_get_result() { return HAL_adc_result; }
 
-void flashFirmware(int16_t) { NVIC_SystemReset(); }
+void flashFirmware(const int16_t) { NVIC_SystemReset(); }
 
 #endif // ARDUINO_ARCH_STM32 && !STM32GENERIC
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index 9fb40d6121879a786ac0163f9a7ad35fd73e2b30..c310cca74e29c74b57920f1965ff67fa34cbd63f 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -223,4 +223,4 @@ uint16_t HAL_adc_get_result();
 #define PARSED_PIN_INDEX(code, dval) parser.intval(code, dval)
 
 #define PLATFORM_M997_SUPPORT
-void flashFirmware(int16_t value);
+void flashFirmware(const int16_t);
diff --git a/Marlin/src/HAL/STM32F1/HAL.cpp b/Marlin/src/HAL/STM32F1/HAL.cpp
index bc5479b60ce0fa71fccff04138623ef8c36c9f54..01fd2c8fc38b4d8c80b839b7a46d88f993867f0e 100644
--- a/Marlin/src/HAL/STM32F1/HAL.cpp
+++ b/Marlin/src/HAL/STM32F1/HAL.cpp
@@ -388,6 +388,6 @@ void analogWrite(pin_t pin, int pwm_val8) {
     analogWrite(uint8_t(pin), pwm_val8);
 }
 
-void flashFirmware(int16_t value) { nvic_sys_reset(); }
+void flashFirmware(const int16_t) { nvic_sys_reset(); }
 
 #endif // __STM32F1__
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index f0f0ce1ea6ac09ac88aeb45c627f10a3c02dd507..ff42beb92af29b0f1ed849d1ad55f666855cd852 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -288,4 +288,4 @@ void analogWrite(pin_t pin, int pwm_val8); // PWM only! mul by 257 in maple!?
 #define JTAGSWD_DISABLE() afio_cfg_debug_ports(AFIO_DEBUG_NONE)
 
 #define PLATFORM_M997_SUPPORT
-void flashFirmware(int16_t value);
+void flashFirmware(const int16_t);