diff --git a/node/node.go b/node/node.go
index d3d8968de..205e672f3 100644
--- a/node/node.go
+++ b/node/node.go
@@ -402,7 +402,7 @@ func (n *Node) OnStart() error {
 	// Add ourselves to addrbook to prevent dialing ourselves
 	n.addrBook.AddOurAddress(nodeInfo.NetAddress())
 
-	// Run the RPC server first
+	// Start the RPC server before the P2P server
 	// so we can eg. receive txs for the first block
 	if n.config.RPC.ListenAddress != "" {
 		listeners, err := n.startRPC()
@@ -412,7 +412,7 @@ func (n *Node) OnStart() error {
 		n.rpcListeners = listeners
 	}
 
-	// Start the switch
+	// Start the switch (the P2P server).
 	err = n.sw.Start()
 	if err != nil {
 		return err
diff --git a/types/part_set.go b/types/part_set.go
index e4f2b9e97..cad3a03fe 100644
--- a/types/part_set.go
+++ b/types/part_set.go
@@ -267,7 +267,7 @@ func (ps *PartSet) StringShort() string {
 
 func (ps *PartSet) MarshalJSON() ([]byte, error) {
 	if ps == nil {
-		return []byte("nil-PartSet"), nil
+		return []byte("{}"), nil
 	}
 
 	ps.mtx.Lock()
@@ -278,6 +278,6 @@ func (ps *PartSet) MarshalJSON() ([]byte, error) {
 		PartsBitArray *cmn.BitArray `json:"parts_bit_array"`
 	}{
 		fmt.Sprintf("%d/%d", ps.Count(), ps.Total()),
-		ps.partsBitArray.Copy(),
+		ps.partsBitArray,
 	})
 }
diff --git a/types/vote_set.go b/types/vote_set.go
index 07ef60ec6..c5c72d435 100644
--- a/types/vote_set.go
+++ b/types/vote_set.go
@@ -56,9 +56,9 @@ type VoteSet struct {
 	height  int64
 	round   int
 	type_   byte
+	valSet  *ValidatorSet
 
 	mtx           sync.Mutex
-	valSet        *ValidatorSet
 	votesBitArray *cmn.BitArray
 	votes         []*Vote                // Primary votes to share
 	sum           int64                  // Sum of voting power for seen votes, discounting conflicts
@@ -399,6 +399,8 @@ func (voteSet *VoteSet) HasTwoThirdsAny() bool {
 }
 
 func (voteSet *VoteSet) HasAll() bool {
+	voteSet.mtx.Lock()
+	defer voteSet.mtx.Unlock()
 	return voteSet.sum == voteSet.valSet.TotalVotingPower()
 }
 
@@ -424,6 +426,8 @@ func (voteSet *VoteSet) String() string {
 }
 
 func (voteSet *VoteSet) StringIndented(indent string) string {
+	voteSet.mtx.Lock()
+	defer voteSet.mtx.Unlock()
 	voteStrings := make([]string, len(voteSet.votes))
 	for i, vote := range voteSet.votes {
 		if vote == nil {
@@ -448,6 +452,8 @@ func (voteSet *VoteSet) StringIndented(indent string) string {
 // Marshal the VoteSet to JSON. Same as String(), just in JSON,
 // and without the height/round/type_ (since its already included in the votes).
 func (voteSet *VoteSet) MarshalJSON() ([]byte, error) {
+	voteSet.mtx.Lock()
+	defer voteSet.mtx.Unlock()
 	voteStrings := make([]string, len(voteSet.votes))
 	for i, vote := range voteSet.votes {
 		if vote == nil {