diff --git a/Sming/Components/FlashString b/Sming/Components/FlashString
index c7f2b606c1..a44b584a10 160000
--- a/Sming/Components/FlashString
+++ b/Sming/Components/FlashString
@@ -1 +1 @@
-Subproject commit c7f2b606c121d757a385b17faa50b7b7367d223a
+Subproject commit a44b584a100848fdb89cc6ea5f1778b4557d3227
diff --git a/Sming/Components/IFS b/Sming/Components/IFS
index 4db9a92b7e..4d30df4bf9 160000
--- a/Sming/Components/IFS
+++ b/Sming/Components/IFS
@@ -1 +1 @@
-Subproject commit 4db9a92b7e893a0406f1c29ca30072adb676e753
+Subproject commit 4d30df4bf9e2bb155009595381d0822bdd81dbfa
diff --git a/Sming/Core/FileSystem.h b/Sming/Core/FileSystem.h
index 211813000f..c2682fc4f2 100644
--- a/Sming/Core/FileSystem.h
+++ b/Sming/Core/FileSystem.h
@@ -235,7 +235,8 @@ template <typename TFileName> inline int fileSetContent(const TFileName& fileNam
 	return fileSystem->setContent(fileName, content, length);
 }
 
-template <typename TFileName, typename TContent> inline int fileSetContent(const TFileName& fileName, TContent content)
+template <typename TFileName, typename TContent>
+inline int fileSetContent(const TFileName& fileName, const TContent& content)
 {
 	CHECK_FS(setContent)
 	return fileSystem->setContent(fileName, content);
diff --git a/docs/source/upgrading/5.1-5.2.rst b/docs/source/upgrading/5.1-5.2.rst
index 0d10a27c14..96f7fc41a4 100644
--- a/docs/source/upgrading/5.1-5.2.rst
+++ b/docs/source/upgrading/5.1-5.2.rst
@@ -75,3 +75,19 @@ Applications must explicitly call :cpp:func:`HttpRequest::onSslInit` and set the
 This extra step ensures that security checks are not unintentionally bypassed.
 
 The same behaviour is now presented when using Bearssl, and will now fail with ``X509_NOT_TRUSTED``.
+
+
+**FlashString copy support removed**
+
+The :library:`FlashString` previously supported copies (references) like this::
+
+   FlashString emptyString;
+   FlashString stringCopy(FS("Inline string"));
+
+   DEFINE_FSTR_DATA_LOCAL(flashHelloData, "Hello");
+   auto myCopy = flashHelloData;
+
+These will now fail to compile.
+Copy construction and assignment has been explicitly deleted so avoid unintentional side-effects.
+
+Objects should always be passed by reference.