diff --git a/ports/atmel-samd/qstrdefsport.h b/ports/atmel-samd/qstrdefsport.h
index 9ff78060068f..2d2c26092348 100644
--- a/ports/atmel-samd/qstrdefsport.h
+++ b/ports/atmel-samd/qstrdefsport.h
@@ -4,7 +4,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
 // *FORMAT-OFF*
diff --git a/ports/broadcom/qstrdefsport.h b/ports/broadcom/qstrdefsport.h
index 738a4500f902..79d7f33276ef 100644
--- a/ports/broadcom/qstrdefsport.h
+++ b/ports/broadcom/qstrdefsport.h
@@ -4,7 +4,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port, only needed if they aren't auto-generated
 
diff --git a/ports/cxd56/qstrdefsport.h b/ports/cxd56/qstrdefsport.h
index 9ff78060068f..2d2c26092348 100644
--- a/ports/cxd56/qstrdefsport.h
+++ b/ports/cxd56/qstrdefsport.h
@@ -4,7 +4,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
 // *FORMAT-OFF*
diff --git a/ports/espressif/qstrdefsport.h b/ports/espressif/qstrdefsport.h
index 9ff78060068f..2d2c26092348 100644
--- a/ports/espressif/qstrdefsport.h
+++ b/ports/espressif/qstrdefsport.h
@@ -4,7 +4,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
 // *FORMAT-OFF*
diff --git a/ports/litex/qstrdefsport.h b/ports/litex/qstrdefsport.h
index 9ff78060068f..2d2c26092348 100644
--- a/ports/litex/qstrdefsport.h
+++ b/ports/litex/qstrdefsport.h
@@ -4,7 +4,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
 // *FORMAT-OFF*
diff --git a/ports/mimxrt10xx/qstrdefsport.h b/ports/mimxrt10xx/qstrdefsport.h
index 9ff78060068f..2d2c26092348 100644
--- a/ports/mimxrt10xx/qstrdefsport.h
+++ b/ports/mimxrt10xx/qstrdefsport.h
@@ -4,7 +4,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
 // *FORMAT-OFF*
diff --git a/ports/nordic/qstrdefsport.h b/ports/nordic/qstrdefsport.h
index b8cd1fd9af90..a754f55f42af 100644
--- a/ports/nordic/qstrdefsport.h
+++ b/ports/nordic/qstrdefsport.h
@@ -4,6 +4,6 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
diff --git a/ports/raspberrypi/qstrdefsport.h b/ports/raspberrypi/qstrdefsport.h
index b8cd1fd9af90..a754f55f42af 100644
--- a/ports/raspberrypi/qstrdefsport.h
+++ b/ports/raspberrypi/qstrdefsport.h
@@ -4,6 +4,6 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
diff --git a/ports/renode/qstrdefsport.h b/ports/renode/qstrdefsport.h
index b8cd1fd9af90..a754f55f42af 100644
--- a/ports/renode/qstrdefsport.h
+++ b/ports/renode/qstrdefsport.h
@@ -4,6 +4,6 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port
diff --git a/ports/stm/qstrdefsport.h b/ports/stm/qstrdefsport.h
index b8cd1fd9af90..a754f55f42af 100644
--- a/ports/stm/qstrdefsport.h
+++ b/ports/stm/qstrdefsport.h
@@ -4,6 +4,6 @@
 //
 // SPDX-License-Identifier: MIT
 
-#pragma once
+// Do not use #pragma once in this file; it will cause a warning during qstr generation.
 
 // qstrs specific to this port