diff --git a/chain/gen/genesis/genesis.go b/chain/gen/genesis/genesis.go
index a1956f71c..1f6c9db24 100644
--- a/chain/gen/genesis/genesis.go
+++ b/chain/gen/genesis/genesis.go
@@ -94,6 +94,11 @@ func MakeInitialStateTree(ctx context.Context, bs bstore.Blockstore, template ge
 	// Create empty state tree
 
 	cst := cbor.NewCborStore(bs)
+	_, err := cst.Put(context.TODO(), []struct{}{})
+	if err != nil {
+		return nil, xerrors.Errorf("putting empty object: %w", err)
+	}
+
 	state, err := state.NewStateTree(cst)
 	if err != nil {
 		return nil, xerrors.Errorf("making new state tree: %w", err)
diff --git a/chain/vm/mkactor.go b/chain/vm/mkactor.go
index 3f695378a..773163714 100644
--- a/chain/vm/mkactor.go
+++ b/chain/vm/mkactor.go
@@ -16,7 +16,7 @@ import (
 
 func init() {
 	cst := cbor.NewMemCborStore()
-	emptyobject, err := cst.Put(context.TODO(), map[string]string{})
+	emptyobject, err := cst.Put(context.TODO(), []struct{}{})
 	if err != nil {
 		panic(err)
 	}
diff --git a/go.mod b/go.mod
index 8473b74d9..f8b9aa1b7 100644
--- a/go.mod
+++ b/go.mod
@@ -23,7 +23,7 @@ require (
 	github.com/filecoin-project/go-paramfetch v0.0.1
 	github.com/filecoin-project/go-sectorbuilder v0.0.2-0.20200210220012-eb75ec747d6b
 	github.com/filecoin-project/go-statestore v0.1.0
-	github.com/filecoin-project/specs-actors v0.0.0-20200217084223-58b973dc2c1f
+	github.com/filecoin-project/specs-actors v0.0.0-20200217171557-6190f3bd509b
 	github.com/gbrlsnchs/jwt/v3 v3.0.0-beta.1
 	github.com/go-ole/go-ole v1.2.4 // indirect
 	github.com/gorilla/mux v1.7.3
diff --git a/go.sum b/go.sum
index 3acf54aa0..fdf6502cc 100644
--- a/go.sum
+++ b/go.sum
@@ -136,6 +136,8 @@ github.com/filecoin-project/specs-actors v0.0.0-20200217082309-eacd01300b6d h1:6
 github.com/filecoin-project/specs-actors v0.0.0-20200217082309-eacd01300b6d/go.mod h1:xtDZUB6pe4Pksa/bAJbJ693OilaC5Wbot9jMhLm3cZA=
 github.com/filecoin-project/specs-actors v0.0.0-20200217084223-58b973dc2c1f h1:YGhskEZ/N8rKrU85BvUgRuubhykawibsNluzqZSosHE=
 github.com/filecoin-project/specs-actors v0.0.0-20200217084223-58b973dc2c1f/go.mod h1:xtDZUB6pe4Pksa/bAJbJ693OilaC5Wbot9jMhLm3cZA=
+github.com/filecoin-project/specs-actors v0.0.0-20200217171557-6190f3bd509b h1:7TpLVtW0BBiTacx4Vnjn8dX/Ahfl9gLl/XPHN5dxcig=
+github.com/filecoin-project/specs-actors v0.0.0-20200217171557-6190f3bd509b/go.mod h1:xtDZUB6pe4Pksa/bAJbJ693OilaC5Wbot9jMhLm3cZA=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/gbrlsnchs/jwt/v3 v3.0.0-beta.1 h1:EzDjxMg43q1tA2c0MV3tNbaontnHLplHyFF6M5KiVP0=