diff --git a/ethdb/memory_database.go b/ethdb/memory_database.go
index 65c4879347..a2ee2f2ccd 100644
--- a/ethdb/memory_database.go
+++ b/ethdb/memory_database.go
@@ -45,13 +45,6 @@ func (db *MemDatabase) Put(key []byte, value []byte) error {
 	return nil
 }
 
-func (db *MemDatabase) Set(key []byte, value []byte) {
-	db.lock.Lock()
-	defer db.lock.Unlock()
-
-	db.Put(key, value)
-}
-
 func (db *MemDatabase) Get(key []byte) ([]byte, error) {
 	db.lock.RLock()
 	defer db.lock.RUnlock()
diff --git a/trie/errors.go b/trie/errors.go
index e23f9d563a..567b80078c 100644
--- a/trie/errors.go
+++ b/trie/errors.go
@@ -23,24 +23,13 @@ import (
 )
 
 // MissingNodeError is returned by the trie functions (TryGet, TryUpdate, TryDelete)
-// in the case where a trie node is not present in the local database. Contains
-// information necessary for retrieving the missing node through an ODR service.
-//
-// NodeHash is the hash of the missing node
-//
-// RootHash is the original root of the trie that contains the node
-//
-// PrefixLen is the nibble length of the key prefix that leads from the root to
-// the missing node
-//
-// SuffixLen is the nibble length of the remaining part of the key that hints on
-// which further nodes should also be retrieved (can be zero when there are no
-// such hints in the error message)
+// in the case where a trie node is not present in the local database. It contains
+// information necessary for retrieving the missing node.
 type MissingNodeError struct {
-	RootHash, NodeHash   common.Hash
-	PrefixLen, SuffixLen int
+	NodeHash common.Hash // hash of the missing node
+	Path     []byte      // hex-encoded path to the missing node
 }
 
 func (err *MissingNodeError) Error() string {
-	return fmt.Sprintf("Missing trie node %064x", err.NodeHash)
+	return fmt.Sprintf("missing trie node %x (path %x)", err.NodeHash, err.Path)
 }
diff --git a/trie/iterator.go b/trie/iterator.go
index 26ae1d5ad7..76146c0d64 100644
--- a/trie/iterator.go
+++ b/trie/iterator.go
@@ -24,14 +24,13 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 )
 
-var iteratorEnd = errors.New("end of iteration")
-
 // Iterator is a key-value trie iterator that traverses a Trie.
 type Iterator struct {
 	nodeIt NodeIterator
 
 	Key   []byte // Current data key on which the iterator is positioned on
 	Value []byte // Current data value on which the iterator is positioned on
+	Err   error
 }
 
 // NewIterator creates a new key-value iterator from a node iterator
@@ -45,35 +44,42 @@ func NewIterator(it NodeIterator) *Iterator {
 func (it *Iterator) Next() bool {
 	for it.nodeIt.Next(true) {
 		if it.nodeIt.Leaf() {
-			it.Key = hexToKeybytes(it.nodeIt.Path())
+			it.Key = it.nodeIt.LeafKey()
 			it.Value = it.nodeIt.LeafBlob()
 			return true
 		}
 	}
 	it.Key = nil
 	it.Value = nil
+	it.Err = it.nodeIt.Error()
 	return false
 }
 
 // NodeIterator is an iterator to traverse the trie pre-order.
 type NodeIterator interface {
-	// Hash returns the hash of the current node
-	Hash() common.Hash
-	// Parent returns the hash of the parent of the current node
-	Parent() common.Hash
-	// Leaf returns true iff the current node is a leaf node.
-	Leaf() bool
-	// LeafBlob returns the contents of the node, if it is a leaf.
-	// Callers must not retain references to the return value after calling Next()
-	LeafBlob() []byte
-	// Path returns the hex-encoded path to the current node.
-	// Callers must not retain references to the return value after calling Next()
-	Path() []byte
 	// Next moves the iterator to the next node. If the parameter is false, any child
 	// nodes will be skipped.
 	Next(bool) bool
 	// Error returns the error status of the iterator.
 	Error() error
+
+	// Hash returns the hash of the current node.
+	Hash() common.Hash
+	// Parent returns the hash of the parent of the current node. The hash may be the one
+	// grandparent if the immediate parent is an internal node with no hash.
+	Parent() common.Hash
+	// Path returns the hex-encoded path to the current node.
+	// Callers must not retain references to the return value after calling Next.
+	// For leaf nodes, the last element of the path is the 'terminator symbol' 0x10.
+	Path() []byte
+
+	// Leaf returns true iff the current node is a leaf node.
+	// LeafBlob, LeafKey return the contents and key of the leaf node. These
+	// method panic if the iterator is not positioned at a leaf.
+	// Callers must not retain references to their return value after calling Next
+	Leaf() bool
+	LeafBlob() []byte
+	LeafKey() []byte
 }
 
 // nodeIteratorState represents the iteration state at one particular node of the
@@ -89,8 +95,21 @@ type nodeIteratorState struct {
 type nodeIterator struct {
 	trie  *Trie                // Trie being iterated
 	stack []*nodeIteratorState // Hierarchy of trie nodes persisting the iteration state
-	err   error                // Failure set in case of an internal error in the iterator
 	path  []byte               // Path to the current node
+	err   error                // Failure set in case of an internal error in the iterator
+}
+
+// iteratorEnd is stored in nodeIterator.err when iteration is done.
+var iteratorEnd = errors.New("end of iteration")
+
+// seekError is stored in nodeIterator.err if the initial seek has failed.
+type seekError struct {
+	key []byte
+	err error
+}
+
+func (e seekError) Error() string {
+	return "seek error: " + e.err.Error()
 }
 
 func newNodeIterator(trie *Trie, start []byte) NodeIterator {
@@ -98,60 +117,57 @@ func newNodeIterator(trie *Trie, start []byte) NodeIterator {
 		return new(nodeIterator)
 	}
 	it := &nodeIterator{trie: trie}
-	it.seek(start)
+	it.err = it.seek(start)
 	return it
 }
 
-// Hash returns the hash of the current node
 func (it *nodeIterator) Hash() common.Hash {
 	if len(it.stack) == 0 {
 		return common.Hash{}
 	}
-
 	return it.stack[len(it.stack)-1].hash
 }
 
-// Parent returns the hash of the parent node
 func (it *nodeIterator) Parent() common.Hash {
 	if len(it.stack) == 0 {
 		return common.Hash{}
 	}
-
 	return it.stack[len(it.stack)-1].parent
 }
 
-// Leaf returns true if the current node is a leaf
 func (it *nodeIterator) Leaf() bool {
-	if len(it.stack) == 0 {
-		return false
-	}
-
-	_, ok := it.stack[len(it.stack)-1].node.(valueNode)
-	return ok
+	return hasTerm(it.path)
 }
 
-// LeafBlob returns the data for the current node, if it is a leaf
 func (it *nodeIterator) LeafBlob() []byte {
-	if len(it.stack) == 0 {
-		return nil
+	if len(it.stack) > 0 {
+		if node, ok := it.stack[len(it.stack)-1].node.(valueNode); ok {
+			return []byte(node)
+		}
 	}
+	panic("not at leaf")
+}
 
-	if node, ok := it.stack[len(it.stack)-1].node.(valueNode); ok {
-		return []byte(node)
+func (it *nodeIterator) LeafKey() []byte {
+	if len(it.stack) > 0 {
+		if _, ok := it.stack[len(it.stack)-1].node.(valueNode); ok {
+			return hexToKeybytes(it.path)
+		}
 	}
-	return nil
+	panic("not at leaf")
 }
 
-// Path returns the hex-encoded path to the current node
 func (it *nodeIterator) Path() []byte {
 	return it.path
 }
 
-// Error returns the error set in case of an internal error in the iterator
 func (it *nodeIterator) Error() error {
 	if it.err == iteratorEnd {
 		return nil
 	}
+	if seek, ok := it.err.(seekError); ok {
+		return seek.err
+	}
 	return it.err
 }
 
@@ -160,29 +176,37 @@ func (it *nodeIterator) Error() error {
 // sets the Error field to the encountered failure. If `descend` is false,
 // skips iterating over any subnodes of the current node.
 func (it *nodeIterator) Next(descend bool) bool {
-	if it.err != nil {
+	if it.err == iteratorEnd {
 		return false
 	}
-	// Otherwise step forward with the iterator and report any errors
+	if seek, ok := it.err.(seekError); ok {
+		if it.err = it.seek(seek.key); it.err != nil {
+			return false
+		}
+	}
+	// Otherwise step forward with the iterator and report any errors.
 	state, parentIndex, path, err := it.peek(descend)
-	if err != nil {
-		it.err = err
+	it.err = err
+	if it.err != nil {
 		return false
 	}
 	it.push(state, parentIndex, path)
 	return true
 }
 
-func (it *nodeIterator) seek(prefix []byte) {
+func (it *nodeIterator) seek(prefix []byte) error {
 	// The path we're looking for is the hex encoded key without terminator.
 	key := keybytesToHex(prefix)
 	key = key[:len(key)-1]
 	// Move forward until we're just before the closest match to key.
 	for {
 		state, parentIndex, path, err := it.peek(bytes.HasPrefix(key, it.path))
-		if err != nil || bytes.Compare(path, key) >= 0 {
-			it.err = err
-			return
+		if err == iteratorEnd {
+			return iteratorEnd
+		} else if err != nil {
+			return seekError{prefix, err}
+		} else if bytes.Compare(path, key) >= 0 {
+			return nil
 		}
 		it.push(state, parentIndex, path)
 	}
@@ -197,7 +221,8 @@ func (it *nodeIterator) peek(descend bool) (*nodeIteratorState, *int, []byte, er
 		if root != emptyRoot {
 			state.hash = root
 		}
-		return state, nil, nil, nil
+		err := state.resolve(it.trie, nil)
+		return state, nil, nil, err
 	}
 	if !descend {
 		// If we're skipping children, pop the current node first
@@ -205,72 +230,73 @@ func (it *nodeIterator) peek(descend bool) (*nodeIteratorState, *int, []byte, er
 	}
 
 	// Continue iteration to the next child
-	for {
-		if len(it.stack) == 0 {
-			return nil, nil, nil, iteratorEnd
-		}
+	for len(it.stack) > 0 {
 		parent := it.stack[len(it.stack)-1]
 		ancestor := parent.hash
 		if (ancestor == common.Hash{}) {
 			ancestor = parent.parent
 		}
-		if node, ok := parent.node.(*fullNode); ok {
-			// Full node, move to the first non-nil child.
-			for i := parent.index + 1; i < len(node.Children); i++ {
-				child := node.Children[i]
-				if child != nil {
-					hash, _ := child.cache()
-					state := &nodeIteratorState{
-						hash:    common.BytesToHash(hash),
-						node:    child,
-						parent:  ancestor,
-						index:   -1,
-						pathlen: len(it.path),
-					}
-					path := append(it.path, byte(i))
-					parent.index = i - 1
-					return state, &parent.index, path, nil
-				}
+		state, path, ok := it.nextChild(parent, ancestor)
+		if ok {
+			if err := state.resolve(it.trie, path); err != nil {
+				return parent, &parent.index, path, err
 			}
-		} else if node, ok := parent.node.(*shortNode); ok {
-			// Short node, return the pointer singleton child
-			if parent.index < 0 {
-				hash, _ := node.Val.cache()
+			return state, &parent.index, path, nil
+		}
+		// No more child nodes, move back up.
+		it.pop()
+	}
+	return nil, nil, nil, iteratorEnd
+}
+
+func (st *nodeIteratorState) resolve(tr *Trie, path []byte) error {
+	if hash, ok := st.node.(hashNode); ok {
+		resolved, err := tr.resolveHash(hash, path)
+		if err != nil {
+			return err
+		}
+		st.node = resolved
+		st.hash = common.BytesToHash(hash)
+	}
+	return nil
+}
+
+func (it *nodeIterator) nextChild(parent *nodeIteratorState, ancestor common.Hash) (*nodeIteratorState, []byte, bool) {
+	switch node := parent.node.(type) {
+	case *fullNode:
+		// Full node, move to the first non-nil child.
+		for i := parent.index + 1; i < len(node.Children); i++ {
+			child := node.Children[i]
+			if child != nil {
+				hash, _ := child.cache()
 				state := &nodeIteratorState{
 					hash:    common.BytesToHash(hash),
-					node:    node.Val,
+					node:    child,
 					parent:  ancestor,
 					index:   -1,
 					pathlen: len(it.path),
 				}
-				var path []byte
-				if hasTerm(node.Key) {
-					path = append(it.path, node.Key[:len(node.Key)-1]...)
-				} else {
-					path = append(it.path, node.Key...)
-				}
-				return state, &parent.index, path, nil
+				path := append(it.path, byte(i))
+				parent.index = i - 1
+				return state, path, true
 			}
-		} else if hash, ok := parent.node.(hashNode); ok {
-			// Hash node, resolve the hash child from the database
-			if parent.index < 0 {
-				node, err := it.trie.resolveHash(hash, nil, nil)
-				if err != nil {
-					return it.stack[len(it.stack)-1], &parent.index, it.path, err
-				}
-				state := &nodeIteratorState{
-					hash:    common.BytesToHash(hash),
-					node:    node,
-					parent:  ancestor,
-					index:   -1,
-					pathlen: len(it.path),
-				}
-				return state, &parent.index, it.path, nil
+		}
+	case *shortNode:
+		// Short node, return the pointer singleton child
+		if parent.index < 0 {
+			hash, _ := node.Val.cache()
+			state := &nodeIteratorState{
+				hash:    common.BytesToHash(hash),
+				node:    node.Val,
+				parent:  ancestor,
+				index:   -1,
+				pathlen: len(it.path),
 			}
+			path := append(it.path, node.Key...)
+			return state, path, true
 		}
-		// No more child nodes, move back up.
-		it.pop()
 	}
+	return parent, it.path, false
 }
 
 func (it *nodeIterator) push(state *nodeIteratorState, parentIndex *int, path []byte) {
@@ -288,23 +314,21 @@ func (it *nodeIterator) pop() {
 }
 
 func compareNodes(a, b NodeIterator) int {
-	cmp := bytes.Compare(a.Path(), b.Path())
-	if cmp != 0 {
+	if cmp := bytes.Compare(a.Path(), b.Path()); cmp != 0 {
 		return cmp
 	}
-
 	if a.Leaf() && !b.Leaf() {
 		return -1
 	} else if b.Leaf() && !a.Leaf() {
 		return 1
 	}
-
-	cmp = bytes.Compare(a.Hash().Bytes(), b.Hash().Bytes())
-	if cmp != 0 {
+	if cmp := bytes.Compare(a.Hash().Bytes(), b.Hash().Bytes()); cmp != 0 {
 		return cmp
 	}
-
-	return bytes.Compare(a.LeafBlob(), b.LeafBlob())
+	if a.Leaf() && b.Leaf() {
+		return bytes.Compare(a.LeafBlob(), b.LeafBlob())
+	}
+	return 0
 }
 
 type differenceIterator struct {
@@ -341,6 +365,10 @@ func (it *differenceIterator) LeafBlob() []byte {
 	return it.b.LeafBlob()
 }
 
+func (it *differenceIterator) LeafKey() []byte {
+	return it.b.LeafKey()
+}
+
 func (it *differenceIterator) Path() []byte {
 	return it.b.Path()
 }
@@ -410,7 +438,6 @@ func (h *nodeIteratorHeap) Pop() interface{} {
 type unionIterator struct {
 	items *nodeIteratorHeap // Nodes returned are the union of the ones in these iterators
 	count int               // Number of nodes scanned across all tries
-	err   error             // The error, if one has been encountered
 }
 
 // NewUnionIterator constructs a NodeIterator that iterates over elements in the union
@@ -421,9 +448,7 @@ func NewUnionIterator(iters []NodeIterator) (NodeIterator, *int) {
 	copy(h, iters)
 	heap.Init(&h)
 
-	ui := &unionIterator{
-		items: &h,
-	}
+	ui := &unionIterator{items: &h}
 	return ui, &ui.count
 }
 
@@ -443,6 +468,10 @@ func (it *unionIterator) LeafBlob() []byte {
 	return (*it.items)[0].LeafBlob()
 }
 
+func (it *unionIterator) LeafKey() []byte {
+	return (*it.items)[0].LeafKey()
+}
+
 func (it *unionIterator) Path() []byte {
 	return (*it.items)[0].Path()
 }
diff --git a/trie/iterator_test.go b/trie/iterator_test.go
index f161fd99d8..4808d8b0c6 100644
--- a/trie/iterator_test.go
+++ b/trie/iterator_test.go
@@ -19,6 +19,7 @@ package trie
 import (
 	"bytes"
 	"fmt"
+	"math/rand"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -239,8 +240,8 @@ func TestUnionIterator(t *testing.T) {
 
 	all := []struct{ k, v string }{
 		{"aardvark", "c"},
-		{"barb", "bd"},
 		{"barb", "ba"},
+		{"barb", "bd"},
 		{"bard", "bc"},
 		{"bars", "bb"},
 		{"bars", "be"},
@@ -267,3 +268,107 @@ func TestUnionIterator(t *testing.T) {
 		t.Errorf("Iterator returned extra values.")
 	}
 }
+
+func TestIteratorNoDups(t *testing.T) {
+	var tr Trie
+	for _, val := range testdata1 {
+		tr.Update([]byte(val.k), []byte(val.v))
+	}
+	checkIteratorNoDups(t, tr.NodeIterator(nil), nil)
+}
+
+// This test checks that nodeIterator.Next can be retried after inserting missing trie nodes.
+func TestIteratorContinueAfterError(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+	tr, _ := New(common.Hash{}, db)
+	for _, val := range testdata1 {
+		tr.Update([]byte(val.k), []byte(val.v))
+	}
+	tr.Commit()
+	wantNodeCount := checkIteratorNoDups(t, tr.NodeIterator(nil), nil)
+	keys := db.Keys()
+	t.Log("node count", wantNodeCount)
+
+	for i := 0; i < 20; i++ {
+		// Create trie that will load all nodes from DB.
+		tr, _ := New(tr.Hash(), db)
+
+		// Remove a random node from the database. It can't be the root node
+		// because that one is already loaded.
+		var rkey []byte
+		for {
+			if rkey = keys[rand.Intn(len(keys))]; !bytes.Equal(rkey, tr.Hash().Bytes()) {
+				break
+			}
+		}
+		rval, _ := db.Get(rkey)
+		db.Delete(rkey)
+
+		// Iterate until the error is hit.
+		seen := make(map[string]bool)
+		it := tr.NodeIterator(nil)
+		checkIteratorNoDups(t, it, seen)
+		missing, ok := it.Error().(*MissingNodeError)
+		if !ok || !bytes.Equal(missing.NodeHash[:], rkey) {
+			t.Fatal("didn't hit missing node, got", it.Error())
+		}
+
+		// Add the node back and continue iteration.
+		db.Put(rkey, rval)
+		checkIteratorNoDups(t, it, seen)
+		if it.Error() != nil {
+			t.Fatal("unexpected error", it.Error())
+		}
+		if len(seen) != wantNodeCount {
+			t.Fatal("wrong node iteration count, got", len(seen), "want", wantNodeCount)
+		}
+	}
+}
+
+// Similar to the test above, this one checks that failure to create nodeIterator at a
+// certain key prefix behaves correctly when Next is called. The expectation is that Next
+// should retry seeking before returning true for the first time.
+func TestIteratorContinueAfterSeekError(t *testing.T) {
+	// Commit test trie to db, then remove the node containing "bars".
+	db, _ := ethdb.NewMemDatabase()
+	ctr, _ := New(common.Hash{}, db)
+	for _, val := range testdata1 {
+		ctr.Update([]byte(val.k), []byte(val.v))
+	}
+	root, _ := ctr.Commit()
+	barNodeHash := common.HexToHash("05041990364eb72fcb1127652ce40d8bab765f2bfe53225b1170d276cc101c2e")
+	barNode, _ := db.Get(barNodeHash[:])
+	db.Delete(barNodeHash[:])
+
+	// Create a new iterator that seeks to "bars". Seeking can't proceed because
+	// the node is missing.
+	tr, _ := New(root, db)
+	it := tr.NodeIterator([]byte("bars"))
+	missing, ok := it.Error().(*MissingNodeError)
+	if !ok {
+		t.Fatal("want MissingNodeError, got", it.Error())
+	} else if missing.NodeHash != barNodeHash {
+		t.Fatal("wrong node missing")
+	}
+
+	// Reinsert the missing node.
+	db.Put(barNodeHash[:], barNode[:])
+
+	// Check that iteration produces the right set of values.
+	if err := checkIteratorOrder(testdata1[2:], NewIterator(it)); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func checkIteratorNoDups(t *testing.T, it NodeIterator, seen map[string]bool) int {
+	if seen == nil {
+		seen = make(map[string]bool)
+	}
+	for it.Next(true) {
+		if seen[string(it.Path())] {
+			t.Fatalf("iterator visited node path %x twice", it.Path())
+		}
+		seen[string(it.Path())] = true
+	}
+	return len(seen)
+}
diff --git a/trie/proof.go b/trie/proof.go
index fb7734b86d..1f8f76b1b7 100644
--- a/trie/proof.go
+++ b/trie/proof.go
@@ -58,7 +58,7 @@ func (t *Trie) Prove(key []byte) []rlp.RawValue {
 			nodes = append(nodes, n)
 		case hashNode:
 			var err error
-			tn, err = t.resolveHash(n, nil, nil)
+			tn, err = t.resolveHash(n, nil)
 			if err != nil {
 				log.Error(fmt.Sprintf("Unhandled trie error: %v", err))
 				return nil
diff --git a/trie/trie.go b/trie/trie.go
index cbe496574c..a3151b1ce7 100644
--- a/trie/trie.go
+++ b/trie/trie.go
@@ -116,7 +116,7 @@ func New(root common.Hash, db Database) (*Trie, error) {
 		if db == nil {
 			panic("trie.New: cannot use existing root without a database")
 		}
-		rootnode, err := trie.resolveHash(root[:], nil, nil)
+		rootnode, err := trie.resolveHash(root[:], nil)
 		if err != nil {
 			return nil, err
 		}
@@ -180,7 +180,7 @@ func (t *Trie) tryGet(origNode node, key []byte, pos int) (value []byte, newnode
 		}
 		return value, n, didResolve, err
 	case hashNode:
-		child, err := t.resolveHash(n, key[:pos], key[pos:])
+		child, err := t.resolveHash(n, key[:pos])
 		if err != nil {
 			return nil, n, true, err
 		}
@@ -283,7 +283,7 @@ func (t *Trie) insert(n node, prefix, key []byte, value node) (bool, node, error
 		// We've hit a part of the trie that isn't loaded yet. Load
 		// the node and insert into it. This leaves all child nodes on
 		// the path to the value in the trie.
-		rn, err := t.resolveHash(n, prefix, key)
+		rn, err := t.resolveHash(n, prefix)
 		if err != nil {
 			return false, nil, err
 		}
@@ -388,7 +388,7 @@ func (t *Trie) delete(n node, prefix, key []byte) (bool, node, error) {
 				// shortNode{..., shortNode{...}}.  Since the entry
 				// might not be loaded yet, resolve it just for this
 				// check.
-				cnode, err := t.resolve(n.Children[pos], prefix, []byte{byte(pos)})
+				cnode, err := t.resolve(n.Children[pos], prefix)
 				if err != nil {
 					return false, nil, err
 				}
@@ -414,7 +414,7 @@ func (t *Trie) delete(n node, prefix, key []byte) (bool, node, error) {
 		// We've hit a part of the trie that isn't loaded yet. Load
 		// the node and delete from it. This leaves all child nodes on
 		// the path to the value in the trie.
-		rn, err := t.resolveHash(n, prefix, key)
+		rn, err := t.resolveHash(n, prefix)
 		if err != nil {
 			return false, nil, err
 		}
@@ -436,24 +436,19 @@ func concat(s1 []byte, s2 ...byte) []byte {
 	return r
 }
 
-func (t *Trie) resolve(n node, prefix, suffix []byte) (node, error) {
+func (t *Trie) resolve(n node, prefix []byte) (node, error) {
 	if n, ok := n.(hashNode); ok {
-		return t.resolveHash(n, prefix, suffix)
+		return t.resolveHash(n, prefix)
 	}
 	return n, nil
 }
 
-func (t *Trie) resolveHash(n hashNode, prefix, suffix []byte) (node, error) {
+func (t *Trie) resolveHash(n hashNode, prefix []byte) (node, error) {
 	cacheMissCounter.Inc(1)
 
 	enc, err := t.db.Get(n)
 	if err != nil || enc == nil {
-		return nil, &MissingNodeError{
-			RootHash:  t.originalRoot,
-			NodeHash:  common.BytesToHash(n),
-			PrefixLen: len(prefix),
-			SuffixLen: len(suffix),
-		}
+		return nil, &MissingNodeError{NodeHash: common.BytesToHash(n), Path: prefix}
 	}
 	dec := mustDecodeNode(n, enc, t.cachegen)
 	return dec, nil
diff --git a/trie/trie_test.go b/trie/trie_test.go
index 61adbba0ca..1c90950703 100644
--- a/trie/trie_test.go
+++ b/trie/trie_test.go
@@ -19,6 +19,7 @@ package trie
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"math/rand"
@@ -34,7 +35,7 @@ import (
 
 func init() {
 	spew.Config.Indent = "    "
-	spew.Config.DisableMethods = true
+	spew.Config.DisableMethods = false
 }
 
 // Used for testing
@@ -357,6 +358,7 @@ type randTestStep struct {
 	op    int
 	key   []byte // for opUpdate, opDelete, opGet
 	value []byte // for opUpdate
+	err   error  // for debugging
 }
 
 const (
@@ -406,7 +408,7 @@ func runRandTest(rt randTest) bool {
 	tr, _ := New(common.Hash{}, db)
 	values := make(map[string]string) // tracks content of the trie
 
-	for _, step := range rt {
+	for i, step := range rt {
 		switch step.op {
 		case opUpdate:
 			tr.Update(step.key, step.value)
@@ -418,23 +420,22 @@ func runRandTest(rt randTest) bool {
 			v := tr.Get(step.key)
 			want := values[string(step.key)]
 			if string(v) != want {
-				fmt.Printf("mismatch for key 0x%x, got 0x%x want 0x%x", step.key, v, want)
-				return false
+				rt[i].err = fmt.Errorf("mismatch for key 0x%x, got 0x%x want 0x%x", step.key, v, want)
 			}
 		case opCommit:
-			if _, err := tr.Commit(); err != nil {
-				panic(err)
-			}
+			_, rt[i].err = tr.Commit()
 		case opHash:
 			tr.Hash()
 		case opReset:
 			hash, err := tr.Commit()
 			if err != nil {
-				panic(err)
+				rt[i].err = err
+				return false
 			}
 			newtr, err := New(hash, db)
 			if err != nil {
-				panic(err)
+				rt[i].err = err
+				return false
 			}
 			tr = newtr
 		case opItercheckhash:
@@ -444,17 +445,20 @@ func runRandTest(rt randTest) bool {
 				checktr.Update(it.Key, it.Value)
 			}
 			if tr.Hash() != checktr.Hash() {
-				fmt.Println("hashes not equal")
-				return false
+				rt[i].err = fmt.Errorf("hash mismatch in opItercheckhash")
 			}
 		case opCheckCacheInvariant:
-			return checkCacheInvariant(tr.root, nil, tr.cachegen, false, 0)
+			rt[i].err = checkCacheInvariant(tr.root, nil, tr.cachegen, false, 0)
+		}
+		// Abort the test on error.
+		if rt[i].err != nil {
+			return false
 		}
 	}
 	return true
 }
 
-func checkCacheInvariant(n, parent node, parentCachegen uint16, parentDirty bool, depth int) bool {
+func checkCacheInvariant(n, parent node, parentCachegen uint16, parentDirty bool, depth int) error {
 	var children []node
 	var flag nodeFlag
 	switch n := n.(type) {
@@ -465,33 +469,34 @@ func checkCacheInvariant(n, parent node, parentCachegen uint16, parentDirty bool
 		flag = n.flags
 		children = n.Children[:]
 	default:
-		return true
+		return nil
 	}
 
-	showerror := func() {
-		fmt.Printf("at depth %d node %s", depth, spew.Sdump(n))
-		fmt.Printf("parent: %s", spew.Sdump(parent))
+	errorf := func(format string, args ...interface{}) error {
+		msg := fmt.Sprintf(format, args...)
+		msg += fmt.Sprintf("\nat depth %d node %s", depth, spew.Sdump(n))
+		msg += fmt.Sprintf("parent: %s", spew.Sdump(parent))
+		return errors.New(msg)
 	}
 	if flag.gen > parentCachegen {
-		fmt.Printf("cache invariant violation: %d > %d\n", flag.gen, parentCachegen)
-		showerror()
-		return false
+		return errorf("cache invariant violation: %d > %d\n", flag.gen, parentCachegen)
 	}
 	if depth > 0 && !parentDirty && flag.dirty {
-		fmt.Printf("cache invariant violation: child is dirty but parent isn't\n")
-		showerror()
-		return false
+		return errorf("cache invariant violation: %d > %d\n", flag.gen, parentCachegen)
 	}
 	for _, child := range children {
-		if !checkCacheInvariant(child, n, flag.gen, flag.dirty, depth+1) {
-			return false
+		if err := checkCacheInvariant(child, n, flag.gen, flag.dirty, depth+1); err != nil {
+			return err
 		}
 	}
-	return true
+	return nil
 }
 
 func TestRandom(t *testing.T) {
 	if err := quick.Check(runRandTest, nil); err != nil {
+		if cerr, ok := err.(*quick.CheckError); ok {
+			t.Fatalf("random test iteration %d failed: %s", cerr.Count, spew.Sdump(cerr.In))
+		}
 		t.Fatal(err)
 	}
 }