diff --git a/src/github.com/matrix-org/dendrite/cmd/federation-api-proxy/main.go b/src/github.com/matrix-org/dendrite/cmd/federation-api-proxy/main.go
index d1cba69ec..ed0aed722 100644
--- a/src/github.com/matrix-org/dendrite/cmd/federation-api-proxy/main.go
+++ b/src/github.com/matrix-org/dendrite/cmd/federation-api-proxy/main.go
@@ -49,7 +49,7 @@ Arguments:
 var (
 	federationAPIURL = flag.String("federation-api-url", "", "The base URL of the listening 'dendrite-federation-api-server' process. E.g. 'http://localhost:4200'")
 	bindAddress      = flag.String("bind-address", ":8448", "The listening port for the proxy.")
-	certFile         = flag.String("tls-cert", "server.crt", "The X509 certificate to use for TLS")
+	certFile         = flag.String("tls-cert", "server.crt", "The PEM formatted X509 certificate to use for TLS")
 	keyFile          = flag.String("tls-key", "server.key", "The PEM private key to use for TLS")
 )
 
diff --git a/src/github.com/matrix-org/dendrite/federationapi/writers/send.go b/src/github.com/matrix-org/dendrite/federationapi/writers/send.go
index 89acd5b99..fa366c2f0 100644
--- a/src/github.com/matrix-org/dendrite/federationapi/writers/send.go
+++ b/src/github.com/matrix-org/dendrite/federationapi/writers/send.go
@@ -136,7 +136,7 @@ func (t *txnReq) processEvent(e gomatrixserverlib.Event) error {
 
 	if !stateResp.RoomExists {
 		// TODO: When synapse receives a message for a room it is not in it
-		// asked the remote server for the state of the room so that it can
+		// asks the remote server for the state of the room so that it can
 		// check if the remote server knows of a join "m.room.member" event
 		// that this server is unaware of.
 		// However generally speaking we should reject events for rooms we
diff --git a/src/github.com/matrix-org/dendrite/roomserver/input/events.go b/src/github.com/matrix-org/dendrite/roomserver/input/events.go
index 513d10ce5..b379b3aeb 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/input/events.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/input/events.go
@@ -28,7 +28,7 @@ type RoomEventDatabase interface {
 	StoreEvent(event gomatrixserverlib.Event, authEventNIDs []types.EventNID) (types.RoomNID, types.StateAtEvent, error)
 	// Lookup the state entries for a list of string event IDs
 	// Returns an error if the there is an error talking to the database
-	// or if the event IDs aren't in the database.
+	// Returns a types.MissingEventError if the event IDs aren't in the database.
 	StateEntriesForEventIDs(eventIDs []string) ([]types.StateEntry, error)
 	// Set the state at an event.
 	SetState(eventNID types.EventNID, stateNID types.StateSnapshotNID) error
diff --git a/src/github.com/matrix-org/dendrite/roomserver/state/state.go b/src/github.com/matrix-org/dendrite/roomserver/state/state.go
index 6b49aba64..b5454c0cd 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/state/state.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/state/state.go
@@ -32,7 +32,7 @@ type RoomStateDatabase interface {
 	AddState(roomNID types.RoomNID, stateBlockNIDs []types.StateBlockNID, state []types.StateEntry) (types.StateSnapshotNID, error)
 	// Lookup the state of a room at each event for a list of string event IDs.
 	// Returns an error if there is an error talking to the database
-	// or if the room state for the event IDs aren't in the database
+	// Returns a types.MissingEventError if the room state for the event IDs aren't in the database
 	StateAtEventIDs(eventIDs []string) ([]types.StateAtEvent, error)
 	// Lookup the numeric IDs for a list of string event types.
 	// Returns a map from string event type to numeric ID for the event type.
diff --git a/src/github.com/matrix-org/dendrite/roomserver/storage/events_table.go b/src/github.com/matrix-org/dendrite/roomserver/storage/events_table.go
index abbfaac82..a2813ae97 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/storage/events_table.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/storage/events_table.go
@@ -166,6 +166,8 @@ func (s *eventStatements) selectEvent(eventID string) (types.EventNID, types.Sta
 	return types.EventNID(eventNID), types.StateSnapshotNID(stateNID), err
 }
 
+// bulkSelectStateEventByID lookups a list of state events by event ID.
+// If any of the requested events are missing from the database it returns a types.MissingEventError
 func (s *eventStatements) bulkSelectStateEventByID(eventIDs []string) ([]types.StateEntry, error) {
 	rows, err := s.bulkSelectStateEventByIDStmt.Query(pq.StringArray(eventIDs))
 	if err != nil {
@@ -201,6 +203,9 @@ func (s *eventStatements) bulkSelectStateEventByID(eventIDs []string) ([]types.S
 	return results, err
 }
 
+// bulkSelectStateAtEventByID lookups the state at a list of events by event ID.
+// If any of the requested events are missing from the database it returns a types.MissingEventError.
+// If we do not have the state for any of the requested events it returns a types.MissingEventError.
 func (s *eventStatements) bulkSelectStateAtEventByID(eventIDs []string) ([]types.StateAtEvent, error) {
 	rows, err := s.bulkSelectStateAtEventByIDStmt.Query(pq.StringArray(eventIDs))
 	if err != nil {