diff --git a/bridges/bin/millau/runtime/src/rialto_messages.rs b/bridges/bin/millau/runtime/src/rialto_messages.rs
index ccca4222f61d7b5d0247d0c44c581dc4e603b7b5..7054382b3852fa2380f5114e049617d3a0e1d1e1 100644
--- a/bridges/bin/millau/runtime/src/rialto_messages.rs
+++ b/bridges/bin/millau/runtime/src/rialto_messages.rs
@@ -236,7 +236,7 @@ impl messages::BridgedChainWithMessages for Rialto {
 	}
 }
 
-impl TargetHeaderChain<ToRialtoMessagePayload, bp_rialto::AccountId> for Rialto {
+impl TargetHeaderChain<ToRialtoMessagePayload, bp_millau::AccountId> for Rialto {
 	type Error = &'static str;
 	// The proof is:
 	// - hash of the header this proof has been created with;
diff --git a/bridges/bin/millau/runtime/src/rialto_parachain_messages.rs b/bridges/bin/millau/runtime/src/rialto_parachain_messages.rs
index 6840b703f4f4dd5e763bd33ff3cd22b4f8c21f8d..f26e0d1006ae4d7c5239e096327bfc10567b43a8 100644
--- a/bridges/bin/millau/runtime/src/rialto_parachain_messages.rs
+++ b/bridges/bin/millau/runtime/src/rialto_parachain_messages.rs
@@ -229,9 +229,7 @@ impl messages::BridgedChainWithMessages for RialtoParachain {
 	}
 }
 
-impl TargetHeaderChain<ToRialtoParachainMessagePayload, bp_rialto_parachain::AccountId>
-	for RialtoParachain
-{
+impl TargetHeaderChain<ToRialtoParachainMessagePayload, bp_millau::AccountId> for RialtoParachain {
 	type Error = &'static str;
 	// The proof is:
 	// - hash of the header this proof has been created with;
diff --git a/bridges/bin/rialto-parachain/runtime/src/millau_messages.rs b/bridges/bin/rialto-parachain/runtime/src/millau_messages.rs
index 136b4343c190f7621e7251a85428d53eea33acd4..96ff18810bcf4f53498e21d90b3153e0f57a6b32 100644
--- a/bridges/bin/rialto-parachain/runtime/src/millau_messages.rs
+++ b/bridges/bin/rialto-parachain/runtime/src/millau_messages.rs
@@ -243,7 +243,7 @@ impl messages::BridgedChainWithMessages for Millau {
 	}
 }
 
-impl TargetHeaderChain<ToMillauMessagePayload, bp_millau::AccountId> for Millau {
+impl TargetHeaderChain<ToMillauMessagePayload, bp_rialto_parachain::AccountId> for Millau {
 	type Error = &'static str;
 	// The proof is:
 	// - hash of the header this proof has been created with;
diff --git a/bridges/bin/rialto/runtime/src/millau_messages.rs b/bridges/bin/rialto/runtime/src/millau_messages.rs
index 1267cbd06e29f672af22e442bd96af660f239f05..2de74f4c6b9668c074c402a6d855a43fc4896305 100644
--- a/bridges/bin/rialto/runtime/src/millau_messages.rs
+++ b/bridges/bin/rialto/runtime/src/millau_messages.rs
@@ -233,7 +233,7 @@ impl messages::BridgedChainWithMessages for Millau {
 	}
 }
 
-impl TargetHeaderChain<ToMillauMessagePayload, bp_millau::AccountId> for Millau {
+impl TargetHeaderChain<ToMillauMessagePayload, bp_rialto::AccountId> for Millau {
 	type Error = &'static str;
 	// The proof is:
 	// - hash of the header this proof has been created with;
diff --git a/bridges/primitives/messages/src/source_chain.rs b/bridges/primitives/messages/src/source_chain.rs
index c03d303ee84179c6cd290af4e838fc60dc0c62f8..5c6283a803602a63da466f0675c381a112158706 100644
--- a/bridges/primitives/messages/src/source_chain.rs
+++ b/bridges/primitives/messages/src/source_chain.rs
@@ -61,6 +61,10 @@ pub struct RelayerRewards<Balance> {
 /// All implementations of this trait should only work with finalized data that
 /// can't change. Wrong implementation may lead to invalid lane states (i.e. lane
 /// that's stuck) and/or processing messages without paying fees.
+///
+/// The `Payload` type here means the payload of the message that is sent from the
+/// source chain to the target chain. The `AccountId` type here means the account
+/// type used by the source chain.
 pub trait TargetHeaderChain<Payload, AccountId> {
 	/// Error type.
 	type Error: Debug + Into<&'static str>;