diff --git a/src/circuit/pedersen_hash.rs b/src/circuit/pedersen_hash.rs
index 9dfb460..7eec3bb 100644
--- a/src/circuit/pedersen_hash.rs
+++ b/src/circuit/pedersen_hash.rs
@@ -13,7 +13,8 @@ use super::lookup::*;
 // TODO: ensure these match the spec
 pub enum Personalization {
     NoteCommitment,
-    AnotherPersonalization
+    AnotherPersonalization,
+    MerkleTree(usize)
 }
 
 impl Personalization {
@@ -30,6 +31,8 @@ impl Personalization {
                 vec![false, false, false, false, false, false],
             Personalization::AnotherPersonalization =>
                 vec![false, false, false, false, false, true],
+            Personalization::MerkleTree(_) =>
+                vec![false, false, false, false, true, false],
         }
     }
 }
diff --git a/src/jubjub/mod.rs b/src/jubjub/mod.rs
index 13495bc..4782d90 100644
--- a/src/jubjub/mod.rs
+++ b/src/jubjub/mod.rs
@@ -71,7 +71,8 @@ pub enum FixedGenerators {
     ProvingPublicKey = 1,
     ValueCommitmentValue = 2,
     ValueCommitmentRandomness = 3,
-    Max = 4
+    NullifierPosition = 4,
+    Max = 5
 }
 
 pub struct JubjubBls12 {