diff --git a/core/commands/add.go b/core/commands/add.go
index e60df3d1e2c..1bab5472f9e 100644
--- a/core/commands/add.go
+++ b/core/commands/add.go
@@ -158,7 +158,7 @@ You can now refer to the added file in a gateway, like so:
 		rawblks, rbset, _ := req.Option(rawLeavesOptionName).Bool()
 		nocopy, _, _ := req.Option(noCopyOptionName).Bool()
 		fscache, _, _ := req.Option(fstoreCacheOptionName).Bool()
-		cidVerNum, _, _ := req.Option(cidVersionOptionName).Int()
+		cidVer, _, _ := req.Option(cidVersionOptionName).Int()
 
 		if nocopy && !cfg.Experimental.FilestoreEnabled {
 			res.SetError(errors.New("filestore is not enabled, see https://git.io/vy4XN"),
@@ -175,11 +175,11 @@ You can now refer to the added file in a gateway, like so:
 			return
 		}
 
-		if cidVerNum >= 1 && !rbset {
+		if cidVer >= 1 && !rbset {
 			rawblks = true
 		}
 
-		cidVer, err := dag.NewCidVersion(cidVerNum)
+		prefix, err := dag.PrefixForCidVersion(cidVer)
 		if err != nil {
 			res.SetError(err, cmds.ErrNormal)
 			return
@@ -232,7 +232,7 @@ You can now refer to the added file in a gateway, like so:
 		fileAdder.RawLeaves = rawblks
 		fileAdder.NoCopy = nocopy
 
-		fileAdder.SetCidVersion(cidVer)
+		fileAdder.SetPrefix(prefix)
 
 		if hash {
 			md := dagtest.Mock()
diff --git a/core/coreunix/add.go b/core/coreunix/add.go
index 25905980da8..64bc53cbc96 100644
--- a/core/coreunix/add.go
+++ b/core/coreunix/add.go
@@ -110,12 +110,12 @@ type Adder struct {
 	mr         *mfs.Root
 	unlocker   bs.Unlocker
 	tempRoot   *cid.Cid
-	cidVersion dag.CidVersion
+	prefix     cid.Prefix
 }
 
-func (adder *Adder) SetCidVersion(cidVer dag.CidVersion) {
-	adder.mr.SetCidVersion(cidVer)
-	adder.cidVersion = cidVer
+func (adder *Adder) SetPrefix(prefix cid.Prefix) {
+	adder.mr.SetPrefix(prefix)
+	adder.prefix = prefix
 }
 
 func (adder *Adder) SetMfsRoot(r *mfs.Root) {
@@ -130,11 +130,11 @@ func (adder Adder) add(reader io.Reader) (node.Node, error) {
 	}
 
 	params := ihelper.DagBuilderParams{
-		Dagserv:    adder.dagService,
-		RawLeaves:  adder.RawLeaves,
-		Maxlinks:   ihelper.DefaultLinksPerBlock,
-		NoCopy:     adder.NoCopy,
-		CidVersion: adder.cidVersion,
+		Dagserv:   adder.dagService,
+		RawLeaves: adder.RawLeaves,
+		Maxlinks:  ihelper.DefaultLinksPerBlock,
+		NoCopy:    adder.NoCopy,
+		Prefix:    adder.prefix,
 	}
 
 	if adder.Trickle {
@@ -402,7 +402,7 @@ func (adder *Adder) addFile(file files.File) error {
 		}
 
 		dagnode := dag.NodeWithData(sdata)
-		dagnode.SetCidVersion(adder.cidVersion)
+		dagnode.SetPrefix(adder.prefix)
 		_, err = adder.dagService.Add(dagnode)
 		if err != nil {
 			return err
diff --git a/importer/helpers/dagbuilder.go b/importer/helpers/dagbuilder.go
index 4529e040267..f0c7c37e9f5 100644
--- a/importer/helpers/dagbuilder.go
+++ b/importer/helpers/dagbuilder.go
@@ -9,22 +9,23 @@ import (
 	dag "github.com/ipfs/go-ipfs/merkledag"
 	ft "github.com/ipfs/go-ipfs/unixfs"
 
+	cid "gx/ipfs/QmV5gPoRsjN1Gid3LMdNZTyfCtP2DsvqEbMAmz82RmmiGk/go-cid"
 	node "gx/ipfs/QmYDscK7dmdo2GZ9aumS8s5auUUAH5mR1jvj5pYhWusfK7/go-ipld-node"
 )
 
 // DagBuilderHelper wraps together a bunch of objects needed to
 // efficiently create unixfs dag trees
 type DagBuilderHelper struct {
-	dserv      dag.DAGService
-	spl        chunk.Splitter
-	recvdErr   error
-	rawLeaves  bool
-	nextData   []byte // the next item to return.
-	maxlinks   int
-	batch      *dag.Batch
-	fullPath   string
-	stat       os.FileInfo
-	cidVersion dag.CidVersion
+	dserv     dag.DAGService
+	spl       chunk.Splitter
+	recvdErr  error
+	rawLeaves bool
+	nextData  []byte // the next item to return.
+	maxlinks  int
+	batch     *dag.Batch
+	fullPath  string
+	stat      os.FileInfo
+	prefix    cid.Prefix
 }
 
 type DagBuilderParams struct {
@@ -35,8 +36,8 @@ type DagBuilderParams struct {
 	// instead of using the unixfs TRaw type
 	RawLeaves bool
 
-	// CID Version to use
-	CidVersion dag.CidVersion
+	// CID Prefix to use
+	Prefix cid.Prefix
 
 	// DAGService to write blocks to (required)
 	Dagserv dag.DAGService
@@ -50,12 +51,12 @@ type DagBuilderParams struct {
 // from chunks object
 func (dbp *DagBuilderParams) New(spl chunk.Splitter) *DagBuilderHelper {
 	db := &DagBuilderHelper{
-		dserv:      dbp.Dagserv,
-		spl:        spl,
-		rawLeaves:  dbp.RawLeaves,
-		cidVersion: dbp.CidVersion,
-		maxlinks:   dbp.Maxlinks,
-		batch:      dbp.Dagserv.Batch(),
+		dserv:     dbp.Dagserv,
+		spl:       spl,
+		rawLeaves: dbp.RawLeaves,
+		prefix:    dbp.Prefix,
+		maxlinks:  dbp.Maxlinks,
+		batch:     dbp.Dagserv.Batch(),
 	}
 	if fi, ok := spl.Reader().(files.FileInfo); dbp.NoCopy && ok {
 		db.fullPath = fi.AbsPath()
@@ -115,7 +116,7 @@ func (db *DagBuilderHelper) NewUnixfsNode() *UnixfsNode {
 		node: new(dag.ProtoNode),
 		ufmt: &ft.FSNode{Type: ft.TFile},
 	}
-	n.SetCidVersion(db.cidVersion)
+	n.SetPrefix(db.prefix)
 	return n
 }
 
@@ -125,7 +126,7 @@ func (db *DagBuilderHelper) NewUnixfsBlock() *UnixfsNode {
 		node: new(dag.ProtoNode),
 		ufmt: &ft.FSNode{Type: ft.TRaw},
 	}
-	n.SetCidVersion(db.cidVersion)
+	n.SetPrefix(db.prefix)
 	return n
 }
 
diff --git a/importer/helpers/helpers.go b/importer/helpers/helpers.go
index 0253e9d41f7..c7963035ae5 100644
--- a/importer/helpers/helpers.go
+++ b/importer/helpers/helpers.go
@@ -10,6 +10,7 @@ import (
 	pi "github.com/ipfs/go-ipfs/thirdparty/posinfo"
 	ft "github.com/ipfs/go-ipfs/unixfs"
 
+	cid "gx/ipfs/QmV5gPoRsjN1Gid3LMdNZTyfCtP2DsvqEbMAmz82RmmiGk/go-cid"
 	node "gx/ipfs/QmYDscK7dmdo2GZ9aumS8s5auUUAH5mR1jvj5pYhWusfK7/go-ipld-node"
 )
 
@@ -61,8 +62,8 @@ func NewUnixfsNodeFromDag(nd *dag.ProtoNode) (*UnixfsNode, error) {
 	}, nil
 }
 
-func (n *UnixfsNode) SetCidVersion(v dag.CidVersion) {
-	n.node.SetCidVersion(v)
+func (n *UnixfsNode) SetPrefix(prefix cid.Prefix) {
+	n.node.SetPrefix(prefix)
 }
 
 func (n *UnixfsNode) NumChildren() int {
diff --git a/merkledag/cidversion.go b/merkledag/cidversion.go
deleted file mode 100644
index 329ae1bdaf6..00000000000
--- a/merkledag/cidversion.go
+++ /dev/null
@@ -1,23 +0,0 @@
-package merkledag
-
-import (
-	"fmt"
-)
-
-// CidVersion is a a cid version number.  Do not set directly, instead
-// use NewCidVersion to create.  It is safe to panic if it is invalid.
-type CidVersion uint64
-
-const (
-	CID0 CidVersion = 0
-	CID1 CidVersion = 1
-)
-
-func NewCidVersion(version int) (CidVersion, error) {
-	switch version {
-	case 0, 1:
-		return CidVersion(version), nil
-	default:
-		return CidVersion(0), fmt.Errorf("unknown CID version: %d", version)
-	}
-}
diff --git a/merkledag/node.go b/merkledag/node.go
index 16c9b1342b0..e05747da274 100644
--- a/merkledag/node.go
+++ b/merkledag/node.go
@@ -42,16 +42,20 @@ var v1CidPrefix = cid.Prefix{
 	Version:  1,
 }
 
-func (n *ProtoNode) SetCidVersion(v CidVersion) {
-	switch v {
+func PrefixForCidVersion(version int) (cid.Prefix, error) {
+	switch version {
 	case 0:
-		n.Prefix = v0CidPrefix
+		return v0CidPrefix, nil
 	case 1:
-		n.Prefix = v1CidPrefix
+		return v1CidPrefix, nil
 	default:
-		// should not happen
-		panic("unhanded prefix version")
+		return cid.Prefix{}, fmt.Errorf("unknown CID version: %d", version)
 	}
+}
+
+func (n *ProtoNode) SetPrefix(prefix cid.Prefix) {
+	n.Prefix = prefix
+	n.Prefix.Codec = cid.DagProtobuf
 	n.encoded = nil
 	n.cached = nil
 }
diff --git a/mfs/dir.go b/mfs/dir.go
index 6cbea3bce83..aaee3c10ac1 100644
--- a/mfs/dir.go
+++ b/mfs/dir.go
@@ -14,6 +14,7 @@ import (
 	ft "github.com/ipfs/go-ipfs/unixfs"
 	ufspb "github.com/ipfs/go-ipfs/unixfs/pb"
 
+	cid "gx/ipfs/QmV5gPoRsjN1Gid3LMdNZTyfCtP2DsvqEbMAmz82RmmiGk/go-cid"
 	node "gx/ipfs/QmYDscK7dmdo2GZ9aumS8s5auUUAH5mR1jvj5pYhWusfK7/go-ipld-node"
 )
 
@@ -50,8 +51,8 @@ func NewDirectory(ctx context.Context, name string, node *dag.ProtoNode, parent
 	}
 }
 
-func (d *Directory) SetCidVersion(cidVer dag.CidVersion) {
-	d.node.SetCidVersion(cidVer)
+func (d *Directory) SetPrefix(prefix cid.Prefix) {
+	d.node.SetPrefix(prefix)
 }
 
 // closeChild updates the child by the given name to the dag node 'nd'
diff --git a/mfs/ops.go b/mfs/ops.go
index 8132b834ac3..0806d33f942 100644
--- a/mfs/ops.go
+++ b/mfs/ops.go
@@ -134,7 +134,7 @@ func Mkdir(r *Root, pth string, mkparents bool, flush bool) error {
 			if err != nil {
 				return err
 			}
-			mkd.SetCidVersion(r.CidVersion)
+			mkd.SetPrefix(r.Prefix)
 			fsn = mkd
 		} else if err != nil {
 			return err
@@ -153,7 +153,7 @@ func Mkdir(r *Root, pth string, mkparents bool, flush bool) error {
 			return err
 		}
 	}
-	final.SetCidVersion(r.CidVersion)
+	final.SetPrefix(r.Prefix)
 
 	if flush {
 		err := final.Flush()
diff --git a/mfs/system.go b/mfs/system.go
index 4e860d7f646..572b39d9e15 100644
--- a/mfs/system.go
+++ b/mfs/system.go
@@ -61,8 +61,8 @@ type Root struct {
 
 	Type string
 
-	// CID version to use for any children created
-	CidVersion dag.CidVersion
+	// Prefix to use for any children created
+	Prefix cid.Prefix
 }
 
 type PubFunc func(context.Context, *cid.Cid) error
@@ -107,9 +107,9 @@ func NewRoot(parent context.Context, ds dag.DAGService, node *dag.ProtoNode, pf
 // SetCidVersion sets the CidVersion of the root node, and any
 // children created.  To just set the CID version of future children,
 // set CidVersion directly
-func (kr *Root) SetCidVersion(cidVer dag.CidVersion) {
-	kr.node.SetCidVersion(cidVer)
-	kr.CidVersion = cidVer
+func (kr *Root) SetPrefix(prefix cid.Prefix) {
+	kr.node.SetPrefix(prefix)
+	kr.Prefix = prefix
 }
 
 func (kr *Root) GetValue() FSNode {