diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/pin_names.h
index 1d6a9cafaf841..3cf071f62caa9 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/pin_names.h
@@ -6,8 +6,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
-
+// OK to include more than once because FORMAT_PIN may be different.
 
 // define FORMAT_PIN(pin_name) and then include this file.
 
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1015/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1015/pin_names.h
index ee8b47b61afe9..a0bb59e547957 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1015/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1015/pin_names.h
@@ -6,7 +6,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// OK to include more than once because FORMAT_PIN may be different.
 
 
 // define FORMAT_PIN(pin_name) and then include this file.
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/pin_names.h
index 1218cd8ed8db6..45203c59968a8 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/pin_names.h
@@ -6,7 +6,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// OK to include more than once because FORMAT_PIN may be different.
 
 
 // define FORMAT_PIN(pin_name) and then include this file.
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1042/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1042/pin_names.h
index 42f03e02f9119..8a98f4560a6c5 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1042/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1042/pin_names.h
@@ -6,7 +6,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// OK to include more than once because FORMAT_PIN may be different.
 
 
 // define FORMAT_PIN(pin_name) and then include this file.
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1052/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1052/pin_names.h
index 5483206f94f37..41d2d67f81adb 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1052/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1052/pin_names.h
@@ -6,7 +6,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// OK to include more than once because FORMAT_PIN may be different.
 
 
 // define FORMAT_PIN(pin_name) and then include this file.
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/pin_names.h
index 5483206f94f37..41d2d67f81adb 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/pin_names.h
@@ -6,7 +6,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// OK to include more than once because FORMAT_PIN may be different.
 
 
 // define FORMAT_PIN(pin_name) and then include this file.
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1176/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1176/pin_names.h
index ec23d603de7d0..b5a5b86b4ddf8 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1176/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1176/pin_names.h
@@ -6,7 +6,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// OK to include more than once because FORMAT_PIN may be different.
 
 
 // define FORMAT_PIN(pin_name) and then include this file.
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/pin_names.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/pin_names.h
index 22fa6c572964e..ffaa74edc3887 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/pin_names.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/pin_names.h
@@ -5,8 +5,6 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
-
 // OK to include more than once because FORMAT_PIN may be different.
 
 #ifdef MIMXRT1011_SERIES