diff --git a/blockstore/splitstore/markset.go b/blockstore/splitstore/markset.go
index 878deb267..c7c80f6c5 100644
--- a/blockstore/splitstore/markset.go
+++ b/blockstore/splitstore/markset.go
@@ -1,8 +1,6 @@
 package splitstore
 
 import (
-	"path/filepath"
-
 	"golang.org/x/xerrors"
 
 	cid "github.com/ipfs/go-cid"
@@ -30,14 +28,12 @@ func OpenMarkSetEnv(path string, mtype string) (MarkSetEnv, error) {
 	switch mtype {
 	case "bloom":
 		return NewBloomMarkSetEnv(false)
-	case "bloomts":
+	case "bloomts": // thread-safe
 		return NewBloomMarkSetEnv(true)
 	case "map":
 		return NewMapMarkSetEnv(false)
-	case "mapts":
+	case "mapts": // thread-safe
 		return NewMapMarkSetEnv(true)
-	case "bolt":
-		return NewBoltMarkSetEnv(filepath.Join(path, "markset.bolt"))
 	default:
 		return nil, xerrors.Errorf("unknown mark set type %s", mtype)
 	}
diff --git a/blockstore/splitstore/markset_bolt.go b/blockstore/splitstore/markset_bolt.go
deleted file mode 100644
index bac7673b8..000000000
--- a/blockstore/splitstore/markset_bolt.go
+++ /dev/null
@@ -1,124 +0,0 @@
-package splitstore
-
-import (
-	"sync"
-	"time"
-
-	"golang.org/x/xerrors"
-
-	cid "github.com/ipfs/go-cid"
-	bolt "go.etcd.io/bbolt"
-)
-
-const boltMarkSetStaging = 16384
-
-type BoltMarkSetEnv struct {
-	db *bolt.DB
-}
-
-var _ MarkSetEnv = (*BoltMarkSetEnv)(nil)
-
-type BoltMarkSet struct {
-	db       *bolt.DB
-	bucketId []byte
-
-	// cache for batching
-	mx   sync.RWMutex
-	pend map[string]struct{}
-}
-
-var _ MarkSet = (*BoltMarkSet)(nil)
-
-func NewBoltMarkSetEnv(path string) (*BoltMarkSetEnv, error) {
-	db, err := bolt.Open(path, 0644,
-		&bolt.Options{
-			Timeout: 1 * time.Second,
-			NoSync:  true,
-		})
-	if err != nil {
-		return nil, err
-	}
-
-	return &BoltMarkSetEnv{db: db}, nil
-}
-
-func (e *BoltMarkSetEnv) Create(name string, hint int64) (MarkSet, error) {
-	bucketId := []byte(name)
-	err := e.db.Update(func(tx *bolt.Tx) error {
-		_, err := tx.CreateBucketIfNotExists(bucketId)
-		if err != nil {
-			return xerrors.Errorf("error creating bolt db bucket %s: %w", name, err)
-		}
-		return nil
-	})
-
-	if err != nil {
-		return nil, err
-	}
-
-	return &BoltMarkSet{
-		db:       e.db,
-		bucketId: bucketId,
-		pend:     make(map[string]struct{}),
-	}, nil
-}
-
-func (e *BoltMarkSetEnv) Close() error {
-	return e.db.Close()
-}
-
-func (s *BoltMarkSet) Mark(cid cid.Cid) error {
-	s.mx.Lock()
-	defer s.mx.Unlock()
-
-	key := cid.Hash()
-	s.pend[string(key)] = struct{}{}
-
-	if len(s.pend) < boltMarkSetStaging {
-		return nil
-	}
-
-	err := s.db.Batch(func(tx *bolt.Tx) error {
-		b := tx.Bucket(s.bucketId)
-		for key := range s.pend {
-			err := b.Put([]byte(key), markBytes)
-			if err != nil {
-				return err
-			}
-		}
-		return nil
-	})
-
-	if err != nil {
-		return err
-	}
-
-	s.pend = make(map[string]struct{})
-	return nil
-}
-
-func (s *BoltMarkSet) Has(cid cid.Cid) (result bool, err error) {
-	s.mx.RLock()
-	defer s.mx.RUnlock()
-
-	key := cid.Hash()
-	_, result = s.pend[string(key)]
-	if result {
-		return result, nil
-	}
-
-	err = s.db.View(func(tx *bolt.Tx) error {
-		b := tx.Bucket(s.bucketId)
-		v := b.Get(key)
-		result = v != nil
-		return nil
-	})
-
-	return result, err
-}
-
-func (s *BoltMarkSet) Close() error {
-	return s.db.Update(func(tx *bolt.Tx) error {
-		return tx.DeleteBucket(s.bucketId)
-	})
-}
diff --git a/blockstore/splitstore/markset_test.go b/blockstore/splitstore/markset_test.go
index 367ab8d06..d5c01e220 100644
--- a/blockstore/splitstore/markset_test.go
+++ b/blockstore/splitstore/markset_test.go
@@ -8,8 +8,8 @@ import (
 	"github.com/multiformats/go-multihash"
 )
 
-func TestBoltMarkSet(t *testing.T) {
-	testMarkSet(t, "bolt")
+func TestMapMarkSet(t *testing.T) {
+	testMarkSet(t, "map")
 }
 
 func TestBloomMarkSet(t *testing.T) {
diff --git a/blockstore/splitstore/splitstore.go b/blockstore/splitstore/splitstore.go
index 0e1acd679..37793f2cc 100644
--- a/blockstore/splitstore/splitstore.go
+++ b/blockstore/splitstore/splitstore.go
@@ -92,7 +92,8 @@ const (
 type Config struct {
 	// MarkSetType is the type of mark set to use.
 	//
-	// Sane values are: "mapts", "bolt" (if you are memory constrained).
+	// Only current sane value is "mapts", but we may add an option for a disk-backed
+	// markset for memory-constrained situations.
 	MarkSetType string
 
 	// DiscardColdBlocks indicates whether to skip moving cold blocks to the coldstore.