diff --git a/Marlin/src/HAL/STM32/MarlinSerial.cpp b/Marlin/src/HAL/STM32/MarlinSerial.cpp
index c420ce40cf..cfb13f5bb5 100644
--- a/Marlin/src/HAL/STM32/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32/MarlinSerial.cpp
@@ -81,7 +81,7 @@ void MarlinSerial::_rx_complete_irq(serial_t *obj) {
     }
 
     #if ENABLED(EMERGENCY_PARSER)
-      emergency_parser.update(emergency_state, c);
+      emergency_parser.update(static_cast<MSerialT*>(this)->emergency_state, c);
     #endif
   }
 }
diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index 8692e9219e..16111936da 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -614,8 +614,8 @@ inline void manage_inactivity(const bool ignore_stepper_queue=false) {
  */
 void idle(TERN_(ADVANCED_PAUSE_FEATURE, bool no_stepper_sleep/*=false*/)) {
   #if ENABLED(MARLIN_DEV_MODE)
-    static uint8_t idle_depth = 0;
-    if (++idle_depth > 5) SERIAL_ECHOLNPAIR("idle() call depth: ", int(idle_depth));
+    static uint16_t idle_depth = 0;
+    if (++idle_depth > 5) SERIAL_ECHOLNPAIR("idle() call depth: ", idle_depth);
   #endif
 
   // Core Marlin activities
diff --git a/Marlin/src/core/serial_base.h b/Marlin/src/core/serial_base.h
index 220ccae831..f52fa11202 100644
--- a/Marlin/src/core/serial_base.h
+++ b/Marlin/src/core/serial_base.h
@@ -78,13 +78,22 @@ struct SerialBase {
   FORCE_INLINE void write(const char* str)                    { while (*str) write(*str++); }
   FORCE_INLINE void write(const uint8_t* buffer, size_t size) { while (size--) write(*buffer++); }
   FORCE_INLINE void print(const char* str)                    { write(str); }
-  NO_INLINE void print(char c, int base = 0)               { print((long)c, base); }
-  NO_INLINE void print(unsigned char c, int base = 0)      { print((unsigned long)c, base); }
-  NO_INLINE void print(int c, int base = DEC)              { print((long)c, base); }
-  NO_INLINE void print(unsigned int c, int base = DEC)     { print((unsigned long)c, base); }
-  void print(long c, int base = DEC)            { if (!base) write(c); write((const uint8_t*)"-", c < 0); printNumber(c < 0 ? -c : c, base); }
-  void print(unsigned long c, int base = DEC)   { printNumber(c, base); }
-  void print(double c, int digits = 2)          { printFloat(c, digits); }
+  NO_INLINE void print(char c, int base = 0)              { print((long)c, base); }
+  NO_INLINE void print(unsigned char c, int base = 0)     { print((unsigned long)c, base); }
+  NO_INLINE void print(int c, int base = DEC)             { print((long)c, base); }
+  NO_INLINE void print(unsigned int c, int base = DEC)    { print((unsigned long)c, base); }
+  void print(unsigned long c, int base = DEC)             { printNumber(c, base); }
+  void print(double c, int digits = 2)                    { printFloat(c, digits); }
+  void print(long c, int base = DEC)                      {
+    if (!base) {
+      write(c);
+      return;
+    }
+    if (base == DEC && c < 0) {
+      write((uint8_t)'-'); c = -c;
+    }
+    printNumber(c, base);
+  }
 
   NO_INLINE void println(const char s[])                  { print(s); println(); }
   NO_INLINE void println(char c, int base = 0)            { print(c, base); println(); }
@@ -98,6 +107,10 @@ struct SerialBase {
 
   // Print a number with the given base
   void printNumber(unsigned long n, const uint8_t base) {
+    if (!base) {
+      write((uint8_t)n);
+      return;
+    }
     if (n) {
       unsigned char buf[8 * sizeof(long)]; // Enough space for base 2
       int8_t i = 0;
diff --git a/Marlin/src/feature/bedlevel/ubl/ubl.cpp b/Marlin/src/feature/bedlevel/ubl/ubl.cpp
index fba065fed9..b0640e5fa2 100644
--- a/Marlin/src/feature/bedlevel/ubl/ubl.cpp
+++ b/Marlin/src/feature/bedlevel/ubl/ubl.cpp
@@ -150,7 +150,7 @@
     SERIAL_ECHO_SP(7);
     LOOP_L_N(i, GRID_MAX_POINTS_X) {
       if (i < 10) SERIAL_CHAR(' ');
-      SERIAL_ECHO(i);
+      SERIAL_ECHO((int)i);
       SERIAL_ECHO_SP(sp);
     }
     serial_delay(10);
diff --git a/Marlin/src/gcode/calibrate/M48.cpp b/Marlin/src/gcode/calibrate/M48.cpp
index 529d5c75d9..97aea59221 100644
--- a/Marlin/src/gcode/calibrate/M48.cpp
+++ b/Marlin/src/gcode/calibrate/M48.cpp
@@ -240,8 +240,8 @@ void GcodeSuite::M48() {
       sigma = SQRT(dev_sum / (n + 1));
 
       if (verbose_level > 1) {
-        SERIAL_ECHO(n + 1);
-        SERIAL_ECHOPAIR(" of ", int(n_samples));
+        SERIAL_ECHO((int)(n + 1));
+        SERIAL_ECHOPAIR(" of ", (int)n_samples);
         SERIAL_ECHOPAIR_F(": z: ", pz, 3);
         SERIAL_CHAR(' ');
         dev_report(verbose_level > 2, mean, sigma, min, max);
diff --git a/Marlin/src/gcode/host/M115.cpp b/Marlin/src/gcode/host/M115.cpp
index 1b088e7d34..0501f3f60b 100644
--- a/Marlin/src/gcode/host/M115.cpp
+++ b/Marlin/src/gcode/host/M115.cpp
@@ -35,8 +35,8 @@
   static void cap_line(PGM_P const name, bool ena=false) {
     SERIAL_ECHOPGM("Cap:");
     serialprintPGM(name);
-    SERIAL_CHAR(':');
-    SERIAL_ECHOLN(int(ena ? 1 : 0));
+    SERIAL_CHAR(':', ena ? '1' : '0');
+    SERIAL_EOL();
   }
 #endif
 
diff --git a/Marlin/src/module/temperature.cpp b/Marlin/src/module/temperature.cpp
index e1fd00dcd6..c6ed3d3a48 100644
--- a/Marlin/src/module/temperature.cpp
+++ b/Marlin/src/module/temperature.cpp
@@ -2062,7 +2062,7 @@ void Temperature::init() {
       switch (heater_id) {
         case H_BED:     SERIAL_ECHOPGM("bed"); break;
         case H_CHAMBER: SERIAL_ECHOPGM("chamber"); break;
-        default:        SERIAL_ECHO(heater_id);
+        default:        SERIAL_ECHO((int)heater_id);
       }
       SERIAL_ECHOLNPAIR(
         " ; sizeof(running_temp):", sizeof(running_temp),
diff --git a/Marlin/src/module/tool_change.cpp b/Marlin/src/module/tool_change.cpp
index 867ae5d927..4278e6be26 100644
--- a/Marlin/src/module/tool_change.cpp
+++ b/Marlin/src/module/tool_change.cpp
@@ -709,7 +709,7 @@ inline void fast_line_to_current(const AxisEnum fr_axis) { _line_to_current(fr_a
 #if EXTRUDERS
   inline void invalid_extruder_error(const uint8_t e) {
     SERIAL_ECHO_START();
-    SERIAL_CHAR('T'); SERIAL_ECHO(int(e));
+    SERIAL_CHAR('T'); SERIAL_ECHO((int)e);
     SERIAL_CHAR(' '); SERIAL_ECHOLNPGM(STR_INVALID_EXTRUDER);
   }
 #endif
diff --git a/Marlin/src/sd/SdBaseFile.cpp b/Marlin/src/sd/SdBaseFile.cpp
index 270053be3e..7693c52330 100644
--- a/Marlin/src/sd/SdBaseFile.cpp
+++ b/Marlin/src/sd/SdBaseFile.cpp
@@ -926,7 +926,7 @@ int SdBaseFile::peek() {
 // print uint8_t with width 2
 static void print2u(const uint8_t v) {
   if (v < 10) SERIAL_CHAR('0');
-  SERIAL_ECHO(int(v));
+  SERIAL_ECHO((int)v);
 }
 
 /**