diff --git a/contrib/signet/miner b/contrib/signet/miner
index e020c4589c1..155e198ae68 100755
--- a/contrib/signet/miner
+++ b/contrib/signet/miner
@@ -19,7 +19,7 @@ PATH_BASE_TEST_FUNCTIONAL = os.path.abspath(os.path.join(PATH_BASE_CONTRIB_SIGNE
 sys.path.insert(0, PATH_BASE_TEST_FUNCTIONAL)
 
 from test_framework.blocktools import get_witness_script, script_BIP34_coinbase_height # noqa: E402
-from test_framework.messages import CBlock, CBlockHeader, COutPoint, CTransaction, CTxIn, CTxInWitness, CTxOut, from_binary, from_hex, ser_string, ser_uint256, tx_from_hex # noqa: E402
+from test_framework.messages import CBlock, CBlockHeader, COutPoint, CTransaction, CTxIn, CTxInWitness, CTxOut, from_binary, from_hex, ser_string, ser_uint256, tx_from_hex, MAX_SEQUENCE_NONFINAL # noqa: E402
 from test_framework.psbt import PSBT, PSBTMap, PSBT_GLOBAL_UNSIGNED_TX, PSBT_IN_FINAL_SCRIPTSIG, PSBT_IN_FINAL_SCRIPTWITNESS, PSBT_IN_NON_WITNESS_UTXO, PSBT_IN_SIGHASH_TYPE # noqa: E402
 from test_framework.script import CScript, CScriptOp # noqa: E402
 
@@ -102,7 +102,8 @@ def generate_psbt(tmpl, reward_spk, *, blocktime=None, poolid=None):
         scriptSig = CScript(b"" + scriptSig + CScriptOp.encode_op_pushdata(poolid))
 
     cbtx = CTransaction()
-    cbtx.vin = [CTxIn(COutPoint(0, 0xffffffff), scriptSig, 0xffffffff)]
+    cbtx.nLockTime = tmpl["height"] - 1
+    cbtx.vin = [CTxIn(COutPoint(0, 0xffffffff), scriptSig, MAX_SEQUENCE_NONFINAL)]
     cbtx.vout = [CTxOut(tmpl["coinbasevalue"], reward_spk)]
     cbtx.vin[0].nSequence = 2**32-2
     cbtx.rehash()