diff --git a/test/functional/interface_zmq.py b/test/functional/interface_zmq.py
--- a/test/functional/interface_zmq.py
+++ b/test/functional/interface_zmq.py
@@ -8,15 +8,18 @@
 
 from test_framework.address import ADDRESS_BCHREG_UNSPENDABLE
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.messages import CTransaction
+from test_framework.messages import CTransaction, hash256
 from test_framework.util import (
     assert_equal,
     connect_nodes,
-    hash256,
 )
 from time import sleep
 
 
+def hash256_reversed(byte_str):
+    return hash256(byte_str)[::-1]
+
+
 class ZMQSubscriber:
     def __init__(self, socket, topic):
         self.sequence = 0
@@ -105,7 +108,7 @@
 
             # Should receive the generated raw block.
             block = rawblock.receive()
-            assert_equal(genhashes[x], hash256(block[:80]).hex())
+            assert_equal(genhashes[x], hash256_reversed(block[:80]).hex())
 
         if self.is_wallet_compiled():
             self.log.info("Wait for tx from second node")
@@ -119,7 +122,7 @@
 
             # Should receive the broadcasted raw transaction.
             hex = rawtx.receive()
-            assert_equal(payment_txid, hash256(hex).hex())
+            assert_equal(payment_txid, hash256_reversed(hex).hex())
 
         self.log.info("Test the getzmqnotifications RPC")
         assert_equal(self.nodes[0].getzmqnotifications(), [
diff --git a/test/functional/test_framework/util.py b/test/functional/test_framework/util.py
--- a/test/functional/test_framework/util.py
+++ b/test/functional/test_framework/util.py
@@ -8,7 +8,6 @@
 from binascii import unhexlify
 from decimal import Decimal, ROUND_DOWN
 from subprocess import CalledProcessError
-import hashlib
 import inspect
 import json
 import logging
@@ -229,14 +228,6 @@
     return len(bytearray.fromhex(hex_string))
 
 
-def hash256(byte_str):
-    sha256 = hashlib.sha256()
-    sha256.update(byte_str)
-    sha256d = hashlib.sha256()
-    sha256d.update(sha256.digest())
-    return sha256d.digest()[::-1]
-
-
 def hex_str_to_bytes(hex_str):
     return unhexlify(hex_str.encode('ascii'))