diff --git a/files/leveldb.go b/files/leveldb.go
index d2e6e024..db5a7a98 100644
--- a/files/leveldb.go
+++ b/files/leveldb.go
@@ -164,7 +164,7 @@ func ldbGenericReplace(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo
 		cmp := bytes.Compare(newName, oldName)
 
 		if debug {
-			l.Debugf("generic replace; repo=%q node=%x moreFs=%v moreDb=%v cmp=%d newName=%q oldName=%q", repo, node, moreFs, moreDb, cmp, newName, oldName)
+			l.Debugf("generic replace; repo=%q node=%v moreFs=%v moreDb=%v cmp=%d newName=%q oldName=%q", repo, protocol.NodeIDFromBytes(node), moreFs, moreDb, cmp, newName, oldName)
 		}
 
 		switch {
@@ -213,7 +213,7 @@ func ldbReplace(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo) uint6
 	return ldbGenericReplace(db, repo, node, fs, func(db dbReader, batch dbWriter, repo, node, name []byte, dbi iterator.Iterator) uint64 {
 		// Disk has files that we are missing. Remove it.
 		if debug {
-			l.Debugf("delete; repo=%q node=%x name=%q", repo, node, name)
+			l.Debugf("delete; repo=%q node=%v name=%q", repo, protocol.NodeIDFromBytes(node), name)
 		}
 		ldbRemoveFromGlobal(db, batch, repo, node, name)
 		batch.Delete(dbi.Key())
@@ -230,7 +230,7 @@ func ldbReplaceWithDelete(db *leveldb.DB, repo, node []byte, fs []protocol.FileI
 		}
 		if !protocol.IsDeleted(f.Flags) {
 			if debug {
-				l.Debugf("mark deleted; repo=%q node=%x name=%q", repo, node, name)
+				l.Debugf("mark deleted; repo=%q node=%v name=%q", repo, protocol.NodeIDFromBytes(node), name)
 			}
 			ts := clock(f.LocalVersion)
 			f.Blocks = nil
@@ -289,7 +289,7 @@ func ldbUpdate(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo) uint64
 
 func ldbInsert(batch dbWriter, repo, node, name []byte, file protocol.FileInfo) uint64 {
 	if debug {
-		l.Debugf("insert; repo=%q node=%x %v", repo, node, file)
+		l.Debugf("insert; repo=%q node=%v %v", repo, protocol.NodeIDFromBytes(node), file)
 	}
 
 	if file.LocalVersion == 0 {
@@ -307,7 +307,7 @@ func ldbInsert(batch dbWriter, repo, node, name []byte, file protocol.FileInfo)
 // If the file does not have an entry in the global list, it is created.
 func ldbUpdateGlobal(db dbReader, batch dbWriter, repo, node, file []byte, version uint64) bool {
 	if debug {
-		l.Debugf("update global; repo=%q node=%x file=%q version=%d", repo, node, file, version)
+		l.Debugf("update global; repo=%q node=%v file=%q version=%d", repo, protocol.NodeIDFromBytes(node), file, version)
 	}
 	gk := globalKey(repo, file)
 	svl, err := db.Get(gk, nil)
@@ -361,7 +361,7 @@ done:
 // removed entirely.
 func ldbRemoveFromGlobal(db dbReader, batch dbWriter, repo, node, file []byte) {
 	if debug {
-		l.Debugf("remove from global; repo=%q node=%x file=%q", repo, node, file)
+		l.Debugf("remove from global; repo=%q node=%v file=%q", repo, protocol.NodeIDFromBytes(node), file)
 	}
 
 	gk := globalKey(repo, file)
@@ -589,8 +589,7 @@ func ldbAvailability(db *leveldb.DB, repo, file []byte) []protocol.NodeID {
 		if v.version != vl.versions[0].version {
 			break
 		}
-		var n protocol.NodeID
-		copy(n[:], v.node)
+		n := protocol.NodeIDFromBytes(v.node)
 		nodes = append(nodes, n)
 	}
 
@@ -634,7 +633,7 @@ func ldbWithNeed(db *leveldb.DB, repo, node []byte, fn fileIterator) {
 		if need || !have {
 			name := globalKeyName(dbi.Key())
 			if debug {
-				l.Debugf("need repo=%q node=%x name=%q need=%v have=%v haveV=%d globalV=%d", repo, node, name, need, have, haveVersion, vl.versions[0].version)
+				l.Debugf("need repo=%q node=%v name=%q need=%v have=%v haveV=%d globalV=%d", repo, protocol.NodeIDFromBytes(node), name, need, have, haveVersion, vl.versions[0].version)
 			}
 			fk := nodeKey(repo, vl.versions[0].node, name)
 			bs, err := snap.Get(fk, nil)
diff --git a/integration/test-delupd.sh b/integration/test-delupd.sh
index 7d18522e..fb9e1a59 100755
--- a/integration/test-delupd.sh
+++ b/integration/test-delupd.sh
@@ -17,7 +17,7 @@ go build json.go
 start() {
 	echo "Starting..."
 	for i in 1 2 3 ; do
-		STTRACE=files,model,puller,versioner STPROFILER=":909$i" syncthing -home "h$i" > "$i.out" 2>&1 &
+		STTRACE=files,model,puller,versioner,protocol STPROFILER=":909$i" syncthing -home "h$i" > "$i.out" 2>&1 &
 	done
 }
 
diff --git a/protocol/nodeid.go b/protocol/nodeid.go
index be46392e..f3295690 100644
--- a/protocol/nodeid.go
+++ b/protocol/nodeid.go
@@ -31,6 +31,15 @@ func NodeIDFromString(s string) (NodeID, error) {
 	return n, err
 }
 
+func NodeIDFromBytes(bs []byte) NodeID {
+	var n NodeID
+	if len(bs) != len(n) {
+		panic("incorrect length of byte slice representing node ID")
+	}
+	copy(n[:], bs)
+	return n
+}
+
 // String returns the canonical string representation of the node ID
 func (n NodeID) String() string {
 	id := base32.StdEncoding.EncodeToString(n[:])
diff --git a/protocol/protocol.go b/protocol/protocol.go
index 1e131740..3d011fbd 100644
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -327,8 +327,14 @@ func (c *rawConnection) indexSerializerLoop() {
 		select {
 		case ii := <-incomingIndexes:
 			if ii.update {
+				if debug {
+					l.Debugf("calling IndexUpdate(%v, %v, %d files)", ii.id, ii.repo, len(ii.files))
+				}
 				c.receiver.IndexUpdate(ii.id, ii.repo, ii.files)
 			} else {
+				if debug {
+					l.Debugf("calling Index(%v, %v, %d files)", ii.id, ii.repo, len(ii.files))
+				}
 				c.receiver.Index(ii.id, ii.repo, ii.files)
 			}
 		case <-c.closed:
@@ -351,6 +357,9 @@ func (c *rawConnection) handleIndex() error {
 		// update and can't receive the large index update from the
 		// other side.
 
+		if debug {
+			l.Debugf("queueing Index(%v, %v, %d files)", c.id, im.Repository, len(im.Files))
+		}
 		incomingIndexes <- incomingIndex{false, c.id, im.Repository, im.Files}
 	}
 	return nil
@@ -362,6 +371,9 @@ func (c *rawConnection) handleIndexUpdate() error {
 	if err := c.xr.Error(); err != nil {
 		return err
 	} else {
+		if debug {
+			l.Debugf("queueing IndexUpdate(%v, %v, %d files)", c.id, im.Repository, len(im.Files))
+		}
 		incomingIndexes <- incomingIndex{true, c.id, im.Repository, im.Files}
 	}
 	return nil