diff --git a/substrate/primitives/externalities/src/lib.rs b/substrate/primitives/externalities/src/lib.rs
index 411ec97a6b82..41ebf8edd150 100644
--- a/substrate/primitives/externalities/src/lib.rs
+++ b/substrate/primitives/externalities/src/lib.rs
@@ -309,6 +309,11 @@ pub trait Externalities: ExtensionStore {
 	///
 	/// Get all the keys that have been read or written to during the benchmark.
 	fn get_read_and_written_keys(&self) -> Vec<(Vec<u8>, u32, u32, bool)>;
+
+	/// Access to `OverlayChanges<H>` for `gear-tasks`.
+	fn gear_overlayed_changes(&self) -> Option<Box<dyn Any + Send>> {
+		None
+	}
 }
 
 /// Extension for the [`Externalities`] trait.
diff --git a/substrate/primitives/state-machine/src/ext.rs b/substrate/primitives/state-machine/src/ext.rs
index 11df46f2a4a3..b3cee955a1fa 100644
--- a/substrate/primitives/state-machine/src/ext.rs
+++ b/substrate/primitives/state-machine/src/ext.rs
@@ -159,7 +159,7 @@ where
 
 impl<'a, H, B> Externalities for Ext<'a, H, B>
 where
-	H: Hasher,
+	H: Hasher + 'static,
 	H::Out: Ord + 'static + codec::Codec,
 	B: Backend<H>,
 {
@@ -651,6 +651,10 @@ where
 	fn get_read_and_written_keys(&self) -> Vec<(Vec<u8>, u32, u32, bool)> {
 		self.backend.get_read_and_written_keys()
 	}
+
+	fn gear_overlayed_changes(&self) -> Option<Box<dyn Any + Send>> {
+		Some(Box::new(self.overlay.clone()))
+	}
 }
 
 impl<'a, H, B> Ext<'a, H, B>
diff --git a/substrate/primitives/state-machine/src/lib.rs b/substrate/primitives/state-machine/src/lib.rs
index 94c89382cf60..8c34154c70c1 100644
--- a/substrate/primitives/state-machine/src/lib.rs
+++ b/substrate/primitives/state-machine/src/lib.rs
@@ -224,7 +224,7 @@ mod execution {
 
 	impl<'a, B, H, Exec> StateMachine<'a, B, H, Exec>
 	where
-		H: Hasher,
+		H: Hasher + 'static,
 		H::Out: Ord + 'static + codec::Codec,
 		Exec: CodeExecutor + Clone + 'static,
 		B: Backend<H>,
@@ -331,7 +331,7 @@ mod execution {
 	) -> Result<(Vec<u8>, StorageProof), Box<dyn Error>>
 	where
 		B: AsTrieBackend<H>,
-		H: Hasher,
+		H: Hasher + 'static,
 		H::Out: Ord + 'static + codec::Codec,
 		Exec: CodeExecutor + Clone + 'static,
 	{
@@ -367,7 +367,7 @@ mod execution {
 	) -> Result<(Vec<u8>, StorageProof), Box<dyn Error>>
 	where
 		S: trie_backend_essence::TrieBackendStorage<H>,
-		H: Hasher,
+		H: Hasher + 'static,
 		H::Out: Ord + 'static + codec::Codec,
 		Exec: CodeExecutor + 'static + Clone,
 	{
@@ -429,7 +429,7 @@ mod execution {
 		runtime_code: &RuntimeCode,
 	) -> Result<Vec<u8>, Box<dyn Error>>
 	where
-		H: Hasher,
+		H: Hasher + 'static,
 		H::Out: Ord + 'static + codec::Codec,
 		Exec: CodeExecutor + Clone + 'static,
 	{