diff --git a/lib/bitcoin.py b/lib/bitcoin.py
index 39b339966..002dcdc29 100644
--- a/lib/bitcoin.py
+++ b/lib/bitcoin.py
@@ -706,10 +706,9 @@ def xpub_from_xprv(xprv, testnet=False):
     return EncodeBase58Check(xpub)
 
 
-def bip32_root(mnemonic_seed, testnet=False):
+def bip32_root(seed, testnet=False):
     import hmac
     header_pub, header_priv = _get_headers(testnet)
-    seed = mnemonic_to_seed(mnemonic_seed,'')
     I = hmac.new("Bitcoin seed", seed, hashlib.sha512).digest()
     master_k = I[0:32]
     master_c = I[32:]
diff --git a/lib/tests/test_bitcoin.py b/lib/tests/test_bitcoin.py
index e2227170f..c61df592e 100644
--- a/lib/tests/test_bitcoin.py
+++ b/lib/tests/test_bitcoin.py
@@ -68,7 +68,7 @@ class Test_bitcoin(unittest.TestCase):
         assert xprv == "tprv8jTo9vZtZTSiTo6BBDjeQDgLEaipWPsrhYsQpZYoqqJNPKbCyDewkHJZhkoSHiWYCUf1Gm4TFzQxcG4D6s1J9Hsn4whDK7QYyHHokJeUuac"
 
     def _do_test_bip32(self, seed, sequence, testnet):
-        xprv, xpub = bip32_root(seed, testnet)
+        xprv, xpub = bip32_root(seed.decode('hex'), testnet)
         assert sequence[0:2] == "m/"
         path = 'm'
         sequence = sequence[2:]
diff --git a/lib/wallet.py b/lib/wallet.py
index 09830457f..fc4d6d10e 100644
--- a/lib/wallet.py
+++ b/lib/wallet.py
@@ -1385,7 +1385,7 @@ class BIP39_Wallet(BIP32_Wallet):
 
     def create_master_keys(self, password):
         seed = self.get_seed(password)
-        xprv, xpub = bip32_root(seed)
+        xprv, xpub = bip32_root(mnemonic_to_seed(seed,''))
         xprv, xpub = bip32_private_derivation(xprv, "m/", self.root_derivation)
         self.add_master_public_key(self.root_name, xpub)
         self.add_master_private_key(self.root_name, xprv, password)
@@ -1459,7 +1459,7 @@ class Wallet_2of2(BIP39_Wallet):
 
     def add_cosigner_seed(self, seed, name, password):
         # we don't store the seed, only the master xpriv
-        xprv, xpub = bip32_root(seed)
+        xprv, xpub = bip32_root(mnemonic_to_seed(seed,''))
         xprv, xpub = bip32_private_derivation(xprv, "m/", self.root_derivation)
         self.add_master_public_key(name, xpub)
         self.add_master_private_key(name, xprv, password)