diff --git a/bipentropy/bipentropy.py b/bipentropy/bipentropy.py
index 7a13fbf..727733a 100644
--- a/bipentropy/bipentropy.py
+++ b/bipentropy/bipentropy.py
@@ -24,6 +24,7 @@ import hashlib
 from mnemonic import Mnemonic as bip39
 from pycoin.symbols.btc import network as BTC
 from pycoin.encoding.bytes32 import from_bytes_32, to_bytes_32
+import base58
 
 
 class BIPEntropy(object):
@@ -60,14 +61,21 @@ class BIPEntropy(object):
 
     def bip32_xprv_to_xprv(self, path, xprv_string):
         path = self.__decorate_path(path)
-        node = BTC.parse.bip32_prv(xprv_string).subkey_for_path(path)
+        ent = self.bip32_xprv_to_entropy(path, xprv_string)
 
-        # if API to pycoin hadn't been shitcoined:
-        # return BIP32Node(node.chain_code(), secret_exponent=node.secret_exponent()).hwif()
-
-        node._depth = 0
-        node._parent_fingerprint = bytes(4)
-        node._child_index = 0
+        # From Peter Gray
+        # Taking 64 bytes of the HMAC digest, the first 32 bytes are the chain code, and second 32 bytes are the private
+        # key for BIP32 XPRV value. Child number, depth, and parent fingerprint are forced to zero.
+        prefix = b'\x04\x88\xad\xe4'
+        depth = b'\x00'
+        parent_fingerprint = b'\x00\x00\x00\x00'
+        child_num = b'\x00\x00\x00\x00'
+        chain_code = ent[:32]
+        private_key = b'\x00' + ent[32:]
+        extended_key = prefix + depth + parent_fingerprint + child_num + chain_code + private_key
+        checksum = hashlib.sha256(hashlib.sha256(extended_key).digest()).digest()[:4]
+        derived_xprv_string = base58.b58encode(extended_key + checksum).decode()
+        node = BTC.parse(derived_xprv_string)
 
         return node.hwif(as_private=True)
 
diff --git a/test_entropy.py b/test_entropy.py
index d9e7419..2b62bbb 100644
--- a/test_entropy.py
+++ b/test_entropy.py
@@ -25,6 +25,7 @@ import pytest
 
 XPRV = 'xprv9s21ZrQH143K2LBWUUQRFXhucrQqBpKdRRxNVq2zBqsx8HVqFk2uYo8kmbaLLHRdqtQpUm98uKfu3vca1LqdGhUtyoFnCNkfmXRyPXLjbKb'
 
+
 def test_mnemonic():
     e = bipentropy.BIPEntropy()
     mnemonic = 'install scatter logic circle pencil average fall shoe quantum disease suspect usage'
@@ -58,10 +59,10 @@ def test_entropy_to_mnemonic():
     assert e.entropy_to_bip39(entropy, 24) == words24
 
 def test_wif_from_entropy():
-    # PDG: not sure about this?
     e = bipentropy.BIPEntropy()
-    entropy = e.bip32_xprv_to_entropy("m/83696968'/0'/0'", XPRV)
-    assert e.entropy_to_wif(entropy) == 'L5G6UFMvJaFt1KPvupEtT8TUN2YrFnQJm1LA2nEczWrR7MuoxB1Z'
+    entropy = e.bip32_xprv_to_entropy("m/83696968'/2'/0'", XPRV)
+    entropy = entropy[:32]
+    assert e.entropy_to_wif(entropy) == 'Kzyv4uF39d4Jrw2W7UryTHwZr1zQVNk4dAFyqE6BuMrMh1Za7uhp'
 
 def test_mnemonic():
     e = bipentropy.BIPEntropy()
@@ -83,7 +84,7 @@ def test_mnemonic():
 def test_xprv():
     e = bipentropy.BIPEntropy()
     result = e.bip32_xprv_to_xprv("83696968'/32'/0'", XPRV)
-    assert result == 'xprv9s21ZrQH143K3KJoGoKpsDsWdDNDBKs1wqFymBpCGJtrYXrfKzykGDBadZq5SrNde22F83X9qhFZr4uyV9TptTgLqCBc6XFN9tssphdxVeg'
+    assert result == 'xprv9s21ZrQH143K2srSbCSg4m4kLvPMzcWydgmKEnMmoZUurYuBuYG46c6P71UGXMzmriLzCCBvKQWBUv3vPB3m1SATMhp3uEjXHJ42jFg7myX'
 
 @pytest.mark.parametrize('path, width, expect', [
         ("83696968'/128169'/32'/0'", 32, 'ea3ceb0b02ee8e587779c63f4b7b3a21e950a213f1ec53cab608d13e8796e6dc'),
@@ -99,9 +100,9 @@ def test_bipentropy_applications():
            'near account window bike charge season chef number sketch tomorrow excuse sniff circle vital hockey outdoor supply token'
 
     assert app.xprv(XPRV, 0) == \
-           'xprv9s21ZrQH143K3KJoGoKpsDsWdDNDBKs1wqFymBpCGJtrYXrfKzykGDBadZq5SrNde22F83X9qhFZr4uyV9TptTgLqCBc6XFN9tssphdxVeg'
+           'xprv9s21ZrQH143K2srSbCSg4m4kLvPMzcWydgmKEnMmoZUurYuBuYG46c6P71UGXMzmriLzCCBvKQWBUv3vPB3m1SATMhp3uEjXHJ42jFg7myX'
 
-    assert app.wif(XPRV, 0) == 'L5G6UFMvJaFt1KPvupEtT8TUN2YrFnQJm1LA2nEczWrR7MuoxB1Z'
+    assert app.wif(XPRV, 0) == 'Kzyv4uF39d4Jrw2W7UryTHwZr1zQVNk4dAFyqE6BuMrMh1Za7uhp'
 
     assert app.hex(XPRV, 0, 32) == 'ea3ceb0b02ee8e587779c63f4b7b3a21e950a213f1ec53cab608d13e8796e6dc'