diff --git a/lbry/wallet/server/history.py b/lbry/wallet/server/history.py
index 72952dc53..c3ad1131e 100644
--- a/lbry/wallet/server/history.py
+++ b/lbry/wallet/server/history.py
@@ -16,7 +16,7 @@ from collections import defaultdict
 from functools import partial
 
 from lbry.wallet.server import util
-from lbry.wallet.server.util import pack_be_uint16, unpack_be_uint16_from
+from lbry.wallet.server.util import pack_be_uint32, unpack_be_uint32_from
 from lbry.wallet.server.hash import hash_to_hex_str, HASHX_LEN
 
 
@@ -81,7 +81,7 @@ class History:
 
         keys = []
         for key, hist in self.db.iterator(prefix=b''):
-            flush_id, = unpack_be_uint16_from(key[-2:])
+            flush_id, = unpack_be_uint32_from(key[-2:])
             if flush_id > utxo_flush_count:
                 keys.append(key)
 
@@ -126,7 +126,7 @@ class History:
     def flush(self):
         start_time = time.time()
         self.flush_count += 1
-        flush_id = pack_be_uint16(self.flush_count)
+        flush_id = pack_be_uint32(self.flush_count)
         unflushed = self.unflushed
 
         with self.db.write_batch() as batch:
@@ -250,7 +250,7 @@ class History:
         write_size = 0
         keys_to_delete.update(hist_map)
         for n, chunk in enumerate(util.chunks(full_hist, max_row_size)):
-            key = hashX + pack_be_uint16(n)
+            key = hashX + pack_be_uint32(n)
             if hist_map.get(key) == chunk:
                 keys_to_delete.remove(key)
             else:
@@ -301,8 +301,8 @@ class History:
 
         # Loop over 2-byte prefixes
         cursor = self.comp_cursor
-        while write_size < limit and cursor < 65536:
-            prefix = pack_be_uint16(cursor)
+        while write_size < limit and cursor < (1 << 32):
+            prefix = pack_be_uint32(cursor)
             write_size += self._compact_prefix(prefix, write_items,
                                                keys_to_delete)
             cursor += 1
diff --git a/tests/integration/blockchain/test_wallet_server_sessions.py b/tests/integration/blockchain/test_wallet_server_sessions.py
index 67ff86a48..544e04f51 100644
--- a/tests/integration/blockchain/test_wallet_server_sessions.py
+++ b/tests/integration/blockchain/test_wallet_server_sessions.py
@@ -189,3 +189,13 @@ class TestHubDiscovery(CommandTestCase):
                 ('127.0.0.1', 9988): {}
             }
         )
+
+
+class TestStressFlush(CommandTestCase):
+    async def test_flush_over_66_thousand(self):
+        history = self.conductor.spv_node.server.db.history
+        history.flush_count = 66_000
+        history.flush()
+        self.assertEqual(history.flush_count, 66_001)
+        await self.generate(1)
+        self.assertEqual(history.flush_count, 66_002)