diff --git a/lib/account.py b/lib/account.py
index 705052b5b..bae7fc129 100644
--- a/lib/account.py
+++ b/lib/account.py
@@ -211,9 +211,9 @@ class OldAccount(Account):
     @classmethod
     def get_pubkey_from_mpk(self, mpk, for_change, n):
         z = self.get_sequence(mpk, for_change, n)
-        master_public_key = ecdsa.VerifyingKey.from_string( mpk, curve = SECP256k1 )
-        pubkey_point = master_public_key.pubkey.point + z*curve.generator
-        public_key2 = ecdsa.VerifyingKey.from_public_point( pubkey_point, curve = SECP256k1 )
+        master_public_key = ecdsa.VerifyingKey.from_string(mpk, curve = SECP256k1)
+        pubkey_point = master_public_key.pubkey.point + z*SECP256k1.generator
+        public_key2 = ecdsa.VerifyingKey.from_public_point(pubkey_point, curve = SECP256k1)
         return '04' + public_key2.to_string().encode('hex')
 
     def derive_pubkeys(self, for_change, n):