diff --git a/python/src/trezorlib/transport/thp/protocol_v2.py b/python/src/trezorlib/transport/thp/protocol_v2.py
index 2637a2e064..fc640dfd9e 100644
--- a/python/src/trezorlib/transport/thp/protocol_v2.py
+++ b/python/src/trezorlib/transport/thp/protocol_v2.py
@@ -133,9 +133,7 @@ class ProtocolV2(ProtocolAndChannel):
         self.sync_bit_send = 0
         self.sync_bit_receive = 0
         # Send channel allocation request
-        # Note that [:8] on the following line is required when tests use
-        # WITH_MOCK_URANDOM. Without [:8] such tests will (almost always) fail.
-        channel_id_request_nonce = os.urandom(8)[:8]
+        channel_id_request_nonce = os.urandom(8)
         thp_io.write_payload_to_wire_and_add_checksum(
             self.transport,
             MessageHeader.get_channel_allocation_request_header(12),
@@ -155,9 +153,7 @@ class ProtocolV2(ProtocolAndChannel):
 
         # Send handshake init request
         ha_init_req_header = MessageHeader(0, self.channel_id, 36)
-        # Note that [:32] on the following line is required when tests use
-        # WITH_MOCK_URANDOM. Without [:32] such tests will (almost always) fail.
-        host_ephemeral_privkey = curve25519.get_private_key(os.urandom(32)[:32])
+        host_ephemeral_privkey = curve25519.get_private_key(os.urandom(32))
         host_ephemeral_pubkey = curve25519.get_public_key(host_ephemeral_privkey)
 
         thp_io.write_payload_to_wire_and_add_checksum(