diff --git a/Marlin/src/HAL/DUE/HAL.cpp b/Marlin/src/HAL/DUE/HAL.cpp
index 4b9260c359..6ce85a4643 100644
--- a/Marlin/src/HAL/DUE/HAL.cpp
+++ b/Marlin/src/HAL/DUE/HAL.cpp
@@ -19,9 +19,7 @@
  */
 
 /**
- * Description: HAL for Arduino Due and compatible (SAM3X8E)
- *
- * For ARDUINO_ARCH_SAM
+ * HAL for Arduino Due and compatible (SAM3X8E)
  */
 
 #ifdef ARDUINO_ARCH_SAM
diff --git a/Marlin/src/HAL/DUE/HAL.h b/Marlin/src/HAL/DUE/HAL.h
index 7a057fdae4..dbb84e2ac7 100644
--- a/Marlin/src/HAL/DUE/HAL.h
+++ b/Marlin/src/HAL/DUE/HAL.h
@@ -22,9 +22,7 @@
 #pragma once
 
 /**
- * Description: HAL for Arduino Due and compatible (SAM3X8E)
- *
- * For ARDUINO_ARCH_SAM
+ * HAL for Arduino Due and compatible (SAM3X8E)
  */
 
 #define CPU_32_BIT
diff --git a/Marlin/src/HAL/DUE/HAL_SPI.cpp b/Marlin/src/HAL/DUE/HAL_SPI.cpp
index 54ae8eceb1..0451d8bcc4 100644
--- a/Marlin/src/HAL/DUE/HAL_SPI.cpp
+++ b/Marlin/src/HAL/DUE/HAL_SPI.cpp
@@ -30,7 +30,7 @@
  */
 
 /**
- * Description: HAL for Arduino Due and compatible (SAM3X8E)
+ * HAL for Arduino Due and compatible (SAM3X8E)
  *
  * For ARDUINO_ARCH_SAM
  */
diff --git a/Marlin/src/HAL/DUE/timers.cpp b/Marlin/src/HAL/DUE/timers.cpp
index 795cdad66a..9b937d1a7c 100644
--- a/Marlin/src/HAL/DUE/timers.cpp
+++ b/Marlin/src/HAL/DUE/timers.cpp
@@ -21,9 +21,7 @@
  */
 
 /**
- * Description: HAL for Arduino Due and compatible (SAM3X8E)
- *
- * For ARDUINO_ARCH_SAM
+ * HAL Timers for Arduino Due and compatible (SAM3X8E)
  */
 
 #ifdef ARDUINO_ARCH_SAM
diff --git a/Marlin/src/HAL/DUE/timers.h b/Marlin/src/HAL/DUE/timers.h
index 9defe39a0a..0e1ea07cc2 100644
--- a/Marlin/src/HAL/DUE/timers.h
+++ b/Marlin/src/HAL/DUE/timers.h
@@ -21,9 +21,7 @@
 #pragma once
 
 /**
- * HAL for Arduino Due and compatible (SAM3X8E)
- *
- * For ARDUINO_ARCH_SAM
+ * HAL Timers for Arduino Due and compatible (SAM3X8E)
  */
 
 #include <stdint.h>
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index f6fa46dd93..aa3bcc775d 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -20,7 +20,7 @@
 #pragma once
 
 /**
- * Description: HAL for Espressif ESP32 WiFi
+ * HAL for Espressif ESP32 WiFi
  */
 
 #define CPU_32_BIT
diff --git a/Marlin/src/HAL/TEENSY31_32/HAL.cpp b/Marlin/src/HAL/TEENSY31_32/HAL.cpp
index d276a4c880..8c3dd83377 100644
--- a/Marlin/src/HAL/TEENSY31_32/HAL.cpp
+++ b/Marlin/src/HAL/TEENSY31_32/HAL.cpp
@@ -20,9 +20,8 @@
  *
  */
 
-
 /**
- * Description: HAL for Teensy32 (MK20DX256)
+ * HAL for Teensy 3.2 (MK20DX256)
  */
 
 #ifdef __MK20DX256__
diff --git a/Marlin/src/HAL/TEENSY31_32/HAL.h b/Marlin/src/HAL/TEENSY31_32/HAL.h
index 31ceb8b87c..b434b9de76 100644
--- a/Marlin/src/HAL/TEENSY31_32/HAL.h
+++ b/Marlin/src/HAL/TEENSY31_32/HAL.h
@@ -22,7 +22,7 @@
 #pragma once
 
 /**
- * Description: HAL for Teensy 3.5 and Teensy 3.6
+ * HAL for Teensy 3.2 (MK20DX256)
  */
 
 #define CPU_32_BIT
@@ -44,8 +44,9 @@
 //#undef MOTHERBOARD
 //#define MOTHERBOARD BOARD_TEENSY31_32
 
-#ifdef __MK20DX256__
-  #define IS_32BIT_TEENSY 1
+#define IS_32BIT_TEENSY 1
+#define IS_TEENSY_31_32 1
+#ifndef IS_TEENSY31
   #define IS_TEENSY32 1
 #endif
 
diff --git a/Marlin/src/HAL/TEENSY31_32/Servo.cpp b/Marlin/src/HAL/TEENSY31_32/Servo.cpp
index 544892cb7d..19d57cf1b3 100644
--- a/Marlin/src/HAL/TEENSY31_32/Servo.cpp
+++ b/Marlin/src/HAL/TEENSY31_32/Servo.cpp
@@ -51,5 +51,4 @@ void libServo::move(const int value) {
 }
 
 #endif // HAS_SERVOS
-
 #endif // __MK20DX256__
diff --git a/Marlin/src/HAL/TEENSY31_32/eeprom.cpp b/Marlin/src/HAL/TEENSY31_32/eeprom.cpp
index f663132255..cc5c56f7d5 100644
--- a/Marlin/src/HAL/TEENSY31_32/eeprom.cpp
+++ b/Marlin/src/HAL/TEENSY31_32/eeprom.cpp
@@ -23,8 +23,7 @@
 #if USE_WIRED_EEPROM
 
 /**
- * PersistentStore for Arduino-style EEPROM interface
- * with implementations supplied by the framework.
+ * HAL PersistentStore for Teensy 3.2 (MK20DX256)
  */
 
 #include "../shared/eeprom_api.h"
diff --git a/Marlin/src/HAL/TEENSY31_32/timers.cpp b/Marlin/src/HAL/TEENSY31_32/timers.cpp
index bf756af8a1..7e01a38f89 100644
--- a/Marlin/src/HAL/TEENSY31_32/timers.cpp
+++ b/Marlin/src/HAL/TEENSY31_32/timers.cpp
@@ -21,7 +21,7 @@
  */
 
 /**
- * Teensy3.2 __MK20DX256__
+ * HAL Timers for Teensy 3.2 (MK20DX256)
  */
 
 #ifdef __MK20DX256__
diff --git a/Marlin/src/HAL/TEENSY31_32/timers.h b/Marlin/src/HAL/TEENSY31_32/timers.h
index 4f004ef751..135b328830 100644
--- a/Marlin/src/HAL/TEENSY31_32/timers.h
+++ b/Marlin/src/HAL/TEENSY31_32/timers.h
@@ -22,8 +22,7 @@
 #pragma once
 
 /**
- * Description: HAL for
- * Teensy3.2 (__MK20DX256__)
+ * HAL Timers for Teensy 3.2 (MK20DX256)
  */
 
 #include <stdint.h>
diff --git a/Marlin/src/HAL/TEENSY35_36/HAL.cpp b/Marlin/src/HAL/TEENSY35_36/HAL.cpp
index bcbee1d4c5..92907353b8 100644
--- a/Marlin/src/HAL/TEENSY35_36/HAL.cpp
+++ b/Marlin/src/HAL/TEENSY35_36/HAL.cpp
@@ -21,7 +21,7 @@
  */
 
 /**
- * Description: HAL for Teensy35 (MK64FX512)
+ * HAL for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
  */
 
 #if defined(__MK64FX512__) || defined(__MK66FX1M0__)
diff --git a/Marlin/src/HAL/TEENSY35_36/HAL.h b/Marlin/src/HAL/TEENSY35_36/HAL.h
index 11f0fb941e..f454e7af51 100644
--- a/Marlin/src/HAL/TEENSY35_36/HAL.h
+++ b/Marlin/src/HAL/TEENSY35_36/HAL.h
@@ -22,7 +22,7 @@
 #pragma once
 
 /**
- * Description: HAL for Teensy 3.5 and Teensy 3.6
+ * HAL for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
  */
 
 #define CPU_32_BIT
@@ -45,13 +45,12 @@
 // Defines
 // ------------------------
 
-#ifdef __MK64FX512__
-  #define IS_32BIT_TEENSY 1
-  #define IS_TEENSY35 1
-#endif
+#define IS_32BIT_TEENSY 1
+#define IS_TEENSY_35_36 1
 #ifdef __MK66FX1M0__
-  #define IS_32BIT_TEENSY 1
   #define IS_TEENSY36 1
+#else // __MK64FX512__
+  #define IS_TEENSY35 1
 #endif
 
 #define _MSERIAL(X) Serial##X
diff --git a/Marlin/src/HAL/TEENSY35_36/HAL_SPI.cpp b/Marlin/src/HAL/TEENSY35_36/HAL_SPI.cpp
index 812aa90c83..b36900a321 100644
--- a/Marlin/src/HAL/TEENSY35_36/HAL_SPI.cpp
+++ b/Marlin/src/HAL/TEENSY35_36/HAL_SPI.cpp
@@ -19,6 +19,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
  */
+
+/**
+ * HAL SPI for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
+ */
+
 #if defined(__MK64FX512__) || defined(__MK66FX1M0__)
 
 #include "HAL.h"
diff --git a/Marlin/src/HAL/TEENSY35_36/Servo.cpp b/Marlin/src/HAL/TEENSY35_36/Servo.cpp
index d1390187a7..033858594f 100644
--- a/Marlin/src/HAL/TEENSY35_36/Servo.cpp
+++ b/Marlin/src/HAL/TEENSY35_36/Servo.cpp
@@ -19,6 +19,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
  */
+
+/**
+ * HAL Servo for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
+ */
+
 #if defined(__MK64FX512__) || defined(__MK66FX1M0__)
 
 #include "../../inc/MarlinConfig.h"
@@ -51,5 +56,4 @@ void libServo::move(const int value) {
 }
 
 #endif // HAS_SERVOS
-
 #endif // __MK64FX512__ || __MK66FX1M0__
diff --git a/Marlin/src/HAL/TEENSY35_36/Servo.h b/Marlin/src/HAL/TEENSY35_36/Servo.h
index ae904f0e2e..719011f102 100644
--- a/Marlin/src/HAL/TEENSY35_36/Servo.h
+++ b/Marlin/src/HAL/TEENSY35_36/Servo.h
@@ -21,6 +21,10 @@
  */
 #pragma once
 
+/**
+ * HAL Servo for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
+ */
+
 #include <Servo.h>
 
 // Inherit and expand on core Servo library
diff --git a/Marlin/src/HAL/TEENSY35_36/eeprom.cpp b/Marlin/src/HAL/TEENSY35_36/eeprom.cpp
index d2d7324cdd..ccbdc6b116 100644
--- a/Marlin/src/HAL/TEENSY35_36/eeprom.cpp
+++ b/Marlin/src/HAL/TEENSY35_36/eeprom.cpp
@@ -22,15 +22,14 @@
  */
 #if defined(__MK64FX512__) || defined(__MK66FX1M0__)
 
+/**
+ * HAL PersistentStore for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
+ */
+
 #include "../../inc/MarlinConfig.h"
 
 #if USE_WIRED_EEPROM
 
-/**
- * PersistentStore for Arduino-style EEPROM interface
- * with implementations supplied by the framework.
- */
-
 #include "../shared/eeprom_api.h"
 #include <avr/eeprom.h>
 
diff --git a/Marlin/src/HAL/TEENSY35_36/endstop_interrupts.h b/Marlin/src/HAL/TEENSY35_36/endstop_interrupts.h
index 92e22efc0f..87e6a7507a 100644
--- a/Marlin/src/HAL/TEENSY35_36/endstop_interrupts.h
+++ b/Marlin/src/HAL/TEENSY35_36/endstop_interrupts.h
@@ -22,7 +22,7 @@
 #pragma once
 
 /**
- * Endstop Interrupts
+ * HAL Endstop Interrupts for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
  *
  * Without endstop interrupts the endstop pins must be polled continually in
  * the temperature-ISR via endstops.update(), most of the time finding no change.
diff --git a/Marlin/src/HAL/TEENSY35_36/pinsDebug.h b/Marlin/src/HAL/TEENSY35_36/pinsDebug.h
index e57c73c595..e529fa93be 100644
--- a/Marlin/src/HAL/TEENSY35_36/pinsDebug.h
+++ b/Marlin/src/HAL/TEENSY35_36/pinsDebug.h
@@ -18,6 +18,10 @@
  */
 #pragma once
 
+/**
+ * HAL Pins Debugging for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
+ */
+
 #define NUMBER_PINS_TOTAL NUM_DIGITAL_PINS
 #define MULTI_NAME_PAD 16 // space needed to be pretty if not first name assigned to a pin
 
diff --git a/Marlin/src/HAL/TEENSY35_36/spi_pins.h b/Marlin/src/HAL/TEENSY35_36/spi_pins.h
index 276d4f456a..c76344d075 100644
--- a/Marlin/src/HAL/TEENSY35_36/spi_pins.h
+++ b/Marlin/src/HAL/TEENSY35_36/spi_pins.h
@@ -21,6 +21,10 @@
  */
 #pragma once
 
+/**
+ * HAL SPI Pins for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
+ */
+
 #define SCK_PIN   13
 #define MISO_PIN  12
 #define MOSI_PIN  11
diff --git a/Marlin/src/HAL/TEENSY35_36/timers.cpp b/Marlin/src/HAL/TEENSY35_36/timers.cpp
index 5725e83a85..8067d091dd 100644
--- a/Marlin/src/HAL/TEENSY35_36/timers.cpp
+++ b/Marlin/src/HAL/TEENSY35_36/timers.cpp
@@ -21,8 +21,7 @@
  */
 
 /**
- * Teensy3.5 __MK64FX512__
- * Teensy3.6 __MK66FX1M0__
+ * HAL Timers for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
  */
 
 #if defined(__MK64FX512__) || defined(__MK66FX1M0__)
diff --git a/Marlin/src/HAL/TEENSY35_36/timers.h b/Marlin/src/HAL/TEENSY35_36/timers.h
index ad6629f40d..5c623cd801 100644
--- a/Marlin/src/HAL/TEENSY35_36/timers.h
+++ b/Marlin/src/HAL/TEENSY35_36/timers.h
@@ -21,9 +21,7 @@
 #pragma once
 
 /**
- * Description: HAL for
- * Teensy3.5 (__MK64FX512__)
- * Teensy3.6 (__MK66FX1M0__)
+ * HAL Timers for Teensy 3.5 (MK64FX512) and Teensy 3.6 (MK66FX1M0)
  */
 
 #include <stdint.h>
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.cpp b/Marlin/src/HAL/TEENSY40_41/HAL.cpp
index f5d37f5fc4..5b1b4272f5 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.cpp
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.cpp
@@ -21,7 +21,7 @@
  */
 
 /**
- * Description: HAL for Teensy40 (IMXRT1062)
+ * HAL for Teensy 4.0 / 4.1 (IMXRT1062)
  */
 
 #ifdef __IMXRT1062__
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index b3b0144d13..1aff6eed8e 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -22,7 +22,7 @@
 #pragma once
 
 /**
- * Description: HAL for Teensy 4.0 and Teensy 4.1
+ * HAL for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
  */
 
 #define CPU_32_BIT
@@ -45,8 +45,9 @@
 // Defines
 // ------------------------
 
-#ifdef __IMXRT1062__
-  #define IS_32BIT_TEENSY 1
+#define IS_32BIT_TEENSY 1
+#define IS_TEENSY_40_41 1
+#ifndef IS_TEENSY40
   #define IS_TEENSY41 1
 #endif
 
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL_SPI.cpp b/Marlin/src/HAL/TEENSY40_41/HAL_SPI.cpp
index 9ccbb3a1f4..20b472aa35 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL_SPI.cpp
+++ b/Marlin/src/HAL/TEENSY40_41/HAL_SPI.cpp
@@ -19,6 +19,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
  */
+
+/**
+ * HAL SPI for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
+ */
+
 #ifdef __IMXRT1062__
 
 #include "HAL.h"
diff --git a/Marlin/src/HAL/TEENSY40_41/Servo.cpp b/Marlin/src/HAL/TEENSY40_41/Servo.cpp
index e3d0d03449..ffb1102b14 100644
--- a/Marlin/src/HAL/TEENSY40_41/Servo.cpp
+++ b/Marlin/src/HAL/TEENSY40_41/Servo.cpp
@@ -19,6 +19,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
  */
+
+/**
+ * HAL Servo for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
+ */
+
 #ifdef __IMXRT1062__
 
 #include "../../inc/MarlinConfig.h"
@@ -53,5 +58,4 @@ void libServo::detach() {
 }
 
 #endif // HAS_SERVOS
-
 #endif // __IMXRT1062__
diff --git a/Marlin/src/HAL/TEENSY40_41/Servo.h b/Marlin/src/HAL/TEENSY40_41/Servo.h
index ce910ed8a8..699fd700c9 100644
--- a/Marlin/src/HAL/TEENSY40_41/Servo.h
+++ b/Marlin/src/HAL/TEENSY40_41/Servo.h
@@ -21,6 +21,10 @@
  */
 #pragma once
 
+/**
+ * HAL Servo for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
+ */
+
 #include <PWMServo.h>
 
 // Inherit and expand on core Servo library
diff --git a/Marlin/src/HAL/TEENSY40_41/eeprom.cpp b/Marlin/src/HAL/TEENSY40_41/eeprom.cpp
index 5491e04fbc..030a8c38af 100644
--- a/Marlin/src/HAL/TEENSY40_41/eeprom.cpp
+++ b/Marlin/src/HAL/TEENSY40_41/eeprom.cpp
@@ -27,8 +27,7 @@
 #if USE_WIRED_EEPROM
 
 /**
- * PersistentStore for Arduino-style EEPROM interface
- * with implementations supplied by the framework.
+ * HAL PersistentStore for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
  */
 
 #include "../shared/eeprom_api.h"
diff --git a/Marlin/src/HAL/TEENSY40_41/endstop_interrupts.h b/Marlin/src/HAL/TEENSY40_41/endstop_interrupts.h
index 92e22efc0f..a05e911668 100644
--- a/Marlin/src/HAL/TEENSY40_41/endstop_interrupts.h
+++ b/Marlin/src/HAL/TEENSY40_41/endstop_interrupts.h
@@ -22,7 +22,7 @@
 #pragma once
 
 /**
- * Endstop Interrupts
+ * HAL Endstop Interrupts for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
  *
  * Without endstop interrupts the endstop pins must be polled continually in
  * the temperature-ISR via endstops.update(), most of the time finding no change.
diff --git a/Marlin/src/HAL/TEENSY40_41/fastio.h b/Marlin/src/HAL/TEENSY40_41/fastio.h
index 19b8114509..52f991dfb8 100644
--- a/Marlin/src/HAL/TEENSY40_41/fastio.h
+++ b/Marlin/src/HAL/TEENSY40_41/fastio.h
@@ -23,7 +23,7 @@
 #pragma once
 
 /**
- * Fast I/O interfaces for Teensy 4
+ * Fast I/O interfaces for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
  * These use GPIO functions instead of Direct Port Manipulation, as on AVR.
  */
 
diff --git a/Marlin/src/HAL/TEENSY40_41/pinsDebug.h b/Marlin/src/HAL/TEENSY40_41/pinsDebug.h
index 890f668650..4ad62d00fe 100644
--- a/Marlin/src/HAL/TEENSY40_41/pinsDebug.h
+++ b/Marlin/src/HAL/TEENSY40_41/pinsDebug.h
@@ -18,6 +18,10 @@
  */
 #pragma once
 
+/**
+ * HAL Pins Debugging for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
+ */
+
 #warning "PINS_DEBUGGING is not fully supported for Teensy 4.0 / 4.1 so 'M43' may cause hangs."
 
 #define NUMBER_PINS_TOTAL NUM_DIGITAL_PINS
diff --git a/Marlin/src/HAL/TEENSY40_41/spi_pins.h b/Marlin/src/HAL/TEENSY40_41/spi_pins.h
index 276d4f456a..d6f8d41bf6 100644
--- a/Marlin/src/HAL/TEENSY40_41/spi_pins.h
+++ b/Marlin/src/HAL/TEENSY40_41/spi_pins.h
@@ -21,6 +21,10 @@
  */
 #pragma once
 
+/**
+ * HAL SPI Pins for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
+ */
+
 #define SCK_PIN   13
 #define MISO_PIN  12
 #define MOSI_PIN  11
diff --git a/Marlin/src/HAL/TEENSY40_41/timers.cpp b/Marlin/src/HAL/TEENSY40_41/timers.cpp
index 15f5185a6b..81c9b08c17 100644
--- a/Marlin/src/HAL/TEENSY40_41/timers.cpp
+++ b/Marlin/src/HAL/TEENSY40_41/timers.cpp
@@ -21,7 +21,7 @@
  */
 
 /**
- * Teensy4.0/4.1 (__IMXRT1062__)
+ * HAL Timers for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
  */
 
 #ifdef __IMXRT1062__
diff --git a/Marlin/src/HAL/TEENSY40_41/timers.h b/Marlin/src/HAL/TEENSY40_41/timers.h
index 81891c366b..7e4cd080cb 100644
--- a/Marlin/src/HAL/TEENSY40_41/timers.h
+++ b/Marlin/src/HAL/TEENSY40_41/timers.h
@@ -21,8 +21,7 @@
 #pragma once
 
 /**
- * Description: HAL for
- * Teensy4.0/4.1 (__IMXRT1062__)
+ * HAL Timers for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
  */
 
 #include <stdint.h>
diff --git a/Marlin/src/HAL/TEENSY40_41/watchdog.cpp b/Marlin/src/HAL/TEENSY40_41/watchdog.cpp
index 4253944f2b..8b05ddb153 100644
--- a/Marlin/src/HAL/TEENSY40_41/watchdog.cpp
+++ b/Marlin/src/HAL/TEENSY40_41/watchdog.cpp
@@ -19,6 +19,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
  */
+
+/**
+ * HAL Watchdog for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
+ */
+
 #ifdef __IMXRT1062__
 
 #include "../../inc/MarlinConfig.h"
@@ -48,5 +53,4 @@ void HAL_watchdog_refresh() {
 }
 
 #endif // USE_WATCHDOG
-
 #endif // __IMXRT1062__
diff --git a/Marlin/src/HAL/TEENSY40_41/watchdog.h b/Marlin/src/HAL/TEENSY40_41/watchdog.h
index f10ecb5aef..03ab151b07 100644
--- a/Marlin/src/HAL/TEENSY40_41/watchdog.h
+++ b/Marlin/src/HAL/TEENSY40_41/watchdog.h
@@ -22,7 +22,7 @@
 #pragma once
 
 /**
- * Watchdog for Teensy4.0/4.1 (__IMXRT1062__)
+ * HAL Watchdog for Teensy 4.0 (IMXRT1062DVL6A) / 4.1 (IMXRT1062DVJ6A)
  */
 
 void watchdog_init();
diff --git a/Marlin/src/gcode/calibrate/M100.cpp b/Marlin/src/gcode/calibrate/M100.cpp
index 5ec709fb40..9ac2380e79 100644
--- a/Marlin/src/gcode/calibrate/M100.cpp
+++ b/Marlin/src/gcode/calibrate/M100.cpp
@@ -60,7 +60,7 @@
 
 #define TEST_BYTE ((char) 0xE5)
 
-#if defined(__AVR__) || IS_32BIT_TEENSY
+#if EITHER(__AVR__, IS_32BIT_TEENSY)
 
   extern char __bss_end;
   char *end_bss = &__bss_end,
diff --git a/Marlin/src/pins/teensy3/pins_TEENSY31_32.h b/Marlin/src/pins/teensy3/pins_TEENSY31_32.h
index 45d1231f8e..0edb5cb19d 100644
--- a/Marlin/src/pins/teensy3/pins_TEENSY31_32.h
+++ b/Marlin/src/pins/teensy3/pins_TEENSY31_32.h
@@ -27,7 +27,7 @@
  * https://www.pjrc.com/teensy/teensyduino.html
  */
 
-#if NOT_TARGET(IS_32BIT_TEENSY)
+#if NOT_TARGET(IS_TEENSY_31_32)
   #error "Oops! Select 'Teensy 3.1' or 'Teensy 3.2' in 'Tools > Board.'"
 #endif
 
diff --git a/Marlin/src/pins/teensy3/pins_TEENSY35_36.h b/Marlin/src/pins/teensy3/pins_TEENSY35_36.h
index b1cd3d1612..2e09c8a425 100644
--- a/Marlin/src/pins/teensy3/pins_TEENSY35_36.h
+++ b/Marlin/src/pins/teensy3/pins_TEENSY35_36.h
@@ -27,7 +27,7 @@
 * https://www.pjrc.com/teensy/teensyduino.html
 ****************************************************************************************/
 
-#if NOT_TARGET(IS_32BIT_TEENSY)
+#if NOT_TARGET(IS_TEENSY_35_36)
   #error "Oops! Select 'Teensy 3.5' or 'Teensy 3.6' in 'Tools > Board.'"
 #endif
 
diff --git a/Marlin/src/pins/teensy4/pins_T41U5XBB.h b/Marlin/src/pins/teensy4/pins_T41U5XBB.h
index cb4c0ea879..830637bebd 100644
--- a/Marlin/src/pins/teensy4/pins_T41U5XBB.h
+++ b/Marlin/src/pins/teensy4/pins_T41U5XBB.h
@@ -27,12 +27,12 @@
 * https://www.pjrc.com/teensy/teensyduino.html
 ****************************************************************************************/
 
-#if NOT_TARGET(IS_32BIT_TEENSY) || NOT_TARGET(IS_TEENSY41)
+#if NOT_TARGET(IS_TEENSY41)
   #error "Oops! Select 'Teensy 4.1' in 'Tools > Board.'"
-#else
-  #define BOARD_INFO_NAME "Teensy4.1"
 #endif
 
+#define BOARD_INFO_NAME "Teensy4.1"
+
 /**
  * Plan for Teensy 4.0 and Teensy 4.1:
  *                                     USB
diff --git a/Marlin/src/pins/teensy4/pins_TEENSY41.h b/Marlin/src/pins/teensy4/pins_TEENSY41.h
index cc7341bc23..31c6fda5c9 100644
--- a/Marlin/src/pins/teensy4/pins_TEENSY41.h
+++ b/Marlin/src/pins/teensy4/pins_TEENSY41.h
@@ -27,12 +27,12 @@
 * https://www.pjrc.com/teensy/teensyduino.html
 ****************************************************************************************/
 
-#if NOT_TARGET(IS_32BIT_TEENSY) || NOT_TARGET(IS_TEENSY41)
+#if NOT_TARGET(IS_TEENSY41)
   #error "Oops! Select 'Teensy 4.1' in 'Tools > Board.'"
-#else
-  #define BOARD_INFO_NAME "Teensy4.1"
 #endif
 
+#define BOARD_INFO_NAME "Teensy4.1"
+
 /**
  * Plan for Teensy 4.0 and Teensy 4.1:
  *                                            USB
diff --git a/Marlin/src/sd/Sd2Card.h b/Marlin/src/sd/Sd2Card.h
index da19283ef1..5a7ed375e5 100644
--- a/Marlin/src/sd/Sd2Card.h
+++ b/Marlin/src/sd/Sd2Card.h
@@ -78,13 +78,11 @@ uint8_t const SD_CARD_TYPE_SD1  = 1,                    // Standard capacity V1
               SD_CARD_TYPE_SDHC = 3;                    // High Capacity SD card
 
 /**
- * define SOFTWARE_SPI to use bit-bang SPI
+ * Define SOFTWARE_SPI to use bit-bang SPI
  */
-#if MEGA_SOFT_SPI
+#if EITHER(MEGA_SOFT_SPI, USE_SOFTWARE_SPI)
   #define SOFTWARE_SPI
-#elif USE_SOFTWARE_SPI
-  #define SOFTWARE_SPI
-#endif  // MEGA_SOFT_SPI
+#endif
 
 /**
  * \class Sd2Card
diff --git a/Marlin/src/sd/usb_flashdrive/Sd2Card_FlashDrive.h b/Marlin/src/sd/usb_flashdrive/Sd2Card_FlashDrive.h
index 55a1099a3a..8ca95ba706 100644
--- a/Marlin/src/sd/usb_flashdrive/Sd2Card_FlashDrive.h
+++ b/Marlin/src/sd/usb_flashdrive/Sd2Card_FlashDrive.h
@@ -30,19 +30,20 @@
 #include "../SdInfo.h"
 
 /**
- * define SOFTWARE_SPI to use bit-bang SPI
+ * Define SOFTWARE_SPI to use bit-bang SPI
  */
-#if MEGA_SOFT_SPI || USE_SOFTWARE_SPI
+#if EITHER(MEGA_SOFT_SPI, USE_SOFTWARE_SPI)
   #define SOFTWARE_SPI
 #endif
 
 // SPI pin definitions - do not edit here - change in SdFatConfig.h
-#if DISABLED(SOFTWARE_SPI)
+#if ENABLED(SOFTWARE_SPI)
+  #warning "Auto-assigning '10' as the SD_CHIP_SELECT_PIN."
+  #define SD_CHIP_SELECT_PIN  10                // Software SPI chip select pin for the SD
+#else
   // hardware pin defs
   #define SD_CHIP_SELECT_PIN  SS_PIN            // The default chip select pin for the SD card is SS.
-#else  // SOFTWARE_SPI
-  #define SD_CHIP_SELECT_PIN  10                // Software SPI chip select pin for the SD
-#endif // SOFTWARE_SPI
+#endif
 
 class Sd2Card {
   private:
diff --git a/README.md b/README.md
index 839b9f3f65..27becb9db6 100644
--- a/README.md
+++ b/README.md
@@ -100,8 +100,8 @@ Marlin 2.0 introduces a layer of abstraction so that all the existing high-level
 
   boards|processor|speed|flash|sram|logic|fpu
   ----|---------|-----|-----|----|-----|---
-  [Teensy 4.0](https://www.pjrc.com/store/teensy40.html)|[IMXRT1062](https://www.mouser.com/new/nxp-semiconductors/nxp-imx-rt1060-crossover-processor/) ARM-Cortex M7|600MHz|1M|2M|3.3V|yes
-  [Teensy 4.1](https://www.pjrc.com/store/teensy41.html)|[IMXRT1062](https://www.mouser.com/new/nxp-semiconductors/nxp-imx-rt1060-crossover-processor/) ARM-Cortex M7|600MHz|1M|2M|3.3V|yes
+  [Teensy 4.0](https://www.pjrc.com/store/teensy40.html)|[IMXRT1062DVL6A](https://www.mouser.com/new/nxp-semiconductors/nxp-imx-rt1060-crossover-processor/) ARM-Cortex M7|600MHz|1M|2M|3.3V|yes
+  [Teensy 4.1](https://www.pjrc.com/store/teensy41.html)|[IMXRT1062DVJ6A](https://www.mouser.com/new/nxp-semiconductors/nxp-imx-rt1060-crossover-processor/) ARM-Cortex M7|600MHz|1M|2M|3.3V|yes
 
 ## Submitting Patches