diff --git a/extern/sector-storage/ffiwrapper/sealer_test.go b/extern/sector-storage/ffiwrapper/sealer_test.go
index 2efcfc6a0..39e37f0cc 100644
--- a/extern/sector-storage/ffiwrapper/sealer_test.go
+++ b/extern/sector-storage/ffiwrapper/sealer_test.go
@@ -709,3 +709,46 @@ func BenchmarkAddPiece512M(b *testing.B) {
 		fmt.Println(c)
 	}
 }
+
+func TestAddPiece512MPadded(t *testing.T) {
+	sz := abi.PaddedPieceSize(512 << 20).Unpadded()
+
+	cdir, err := ioutil.TempDir("", "sbtest-c-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	miner := abi.ActorID(123)
+
+	sp := &basicfs.Provider{
+		Root: cdir,
+	}
+	sb, err := New(sp)
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+	cleanup := func() {
+		if t.Failed() {
+			fmt.Printf("not removing %s\n", cdir)
+			return
+		}
+		if err := os.RemoveAll(cdir); err != nil {
+			t.Error(err)
+		}
+	}
+	t.Cleanup(cleanup)
+
+	r := rand.New(rand.NewSource(0x7e5))
+
+	c, err := sb.AddPiece(context.TODO(), storage.SectorRef{
+		ID: abi.SectorID{
+			Miner:  miner,
+			Number: 0,
+		},
+		ProofType: abi.RegisteredSealProof_StackedDrg512MiBV1_1,
+	}, nil, sz, io.LimitReader(r, int64(sz/4)))
+	if err != nil {
+		t.Fatalf("add piece failed: %s", err)
+	}
+
+	require.Equal(t, "baga6ea4seaqonenxyku4o7hr5xkzbqsceipf6xgli3on54beqbk6k246sbooobq", c.PieceCID.String())
+}
diff --git a/go.mod b/go.mod
index 86e6da40d..3c9cfdfc0 100644
--- a/go.mod
+++ b/go.mod
@@ -30,7 +30,7 @@ require (
 	github.com/filecoin-project/go-amt-ipld/v2 v2.1.1-0.20201006184820-924ee87a1349 // indirect
 	github.com/filecoin-project/go-bitfield v0.2.4
 	github.com/filecoin-project/go-cbor-util v0.0.0-20191219014500-08c40a1e63a2
-	github.com/filecoin-project/go-commp-utils v0.1.0
+	github.com/filecoin-project/go-commp-utils v0.1.1-0.20210427180530-4606b1a6cbdd
 	github.com/filecoin-project/go-crypto v0.0.0-20191218222705-effae4ea9f03
 	github.com/filecoin-project/go-data-transfer v1.4.3
 	github.com/filecoin-project/go-fil-commcid v0.0.0-20201016201715-d41df56b4f6a
diff --git a/go.sum b/go.sum
index 8bcfafdfc..7ce7ede20 100644
--- a/go.sum
+++ b/go.sum
@@ -262,6 +262,8 @@ github.com/filecoin-project/go-cbor-util v0.0.0-20191219014500-08c40a1e63a2/go.m
 github.com/filecoin-project/go-commp-utils v0.0.0-20201119054358-b88f7a96a434/go.mod h1:6s95K91mCyHY51RPWECZieD3SGWTqIFLf1mPOes9l5U=
 github.com/filecoin-project/go-commp-utils v0.1.0 h1:PaDxoXYh1TXnnz5kA/xSObpAQwcJSUs4Szb72nuaNdk=
 github.com/filecoin-project/go-commp-utils v0.1.0/go.mod h1:6s95K91mCyHY51RPWECZieD3SGWTqIFLf1mPOes9l5U=
+github.com/filecoin-project/go-commp-utils v0.1.1-0.20210427180530-4606b1a6cbdd h1:cpwbE1z6a+0fp62P0Qv7Z7ZqIy8Jiay0SWR0xcuZ0qs=
+github.com/filecoin-project/go-commp-utils v0.1.1-0.20210427180530-4606b1a6cbdd/go.mod h1:6s95K91mCyHY51RPWECZieD3SGWTqIFLf1mPOes9l5U=
 github.com/filecoin-project/go-crypto v0.0.0-20191218222705-effae4ea9f03 h1:2pMXdBnCiXjfCYx/hLqFxccPoqsSveQFxVLvNxy9bus=
 github.com/filecoin-project/go-crypto v0.0.0-20191218222705-effae4ea9f03/go.mod h1:+viYnvGtUTgJRdy6oaeF4MTFKAfatX071MPDPBL11EQ=
 github.com/filecoin-project/go-data-transfer v1.0.1/go.mod h1:UxvfUAY9v3ub0a21BSK9u3pB2aq30Y0KMsG+w9/ysyo=