diff --git a/lib/mining/miner.js b/lib/mining/miner.js
index fb91cda3..980a5aa4 100644
--- a/lib/mining/miner.js
+++ b/lib/mining/miner.js
@@ -277,32 +277,33 @@ Miner.prototype._createBlock = co(function* createBlock(tip, address) {
   if (!tip)
     tip = this.chain.tip;
 
-  assert(tip);
+  if (!address)
+    address = this.getAddress();
 
   if (version === -1)
     version = yield this.chain.computeBlockVersion(tip);
 
-  ts = Math.max(this.network.now(), tip.ts + 1);
-  locktime = ts;
+  if (this.chain.state.hasMTP()) {
+    locktime = yield tip.getMedianTime();
+    ts = Math.max(this.network.now(), locktime + 1);
+  } else {
+    ts = Math.max(this.network.now(), tip.ts + 1);
+    locktime = ts;
+  }
 
   target = yield this.chain.getTarget(ts, tip);
 
-  if (this.chain.state.hasMTP())
-    locktime = yield tip.getMedianTime();
-
-  if (!address)
-    address = this.getAddress();
-
   attempt = new MinerBlock({
+    network: this.network,
     tip: tip,
     version: version,
+    ts: ts,
     bits: target,
     locktime: locktime,
     flags: this.chain.state.flags,
     address: address,
     coinbaseFlags: this.options.coinbaseFlags,
     witness: this.chain.state.hasWitness(),
-    network: this.network,
     weight: this.options.reservedWeight,
     sigops: this.options.reservedSigops
   });
diff --git a/lib/mining/minerblock.js b/lib/mining/minerblock.js
index 867e5ece..ca91566c 100644
--- a/lib/mining/minerblock.js
+++ b/lib/mining/minerblock.js
@@ -52,6 +52,7 @@ function MinerBlock(options) {
   this.tip = options.tip;
   this.version = options.version;
   this.height = options.tip.height + 1;
+  this.ts = options.ts;
   this.bits = options.bits;
   this.target = consensus.fromCompact(this.bits).toArrayLike(Buffer, 'le', 32);
   this.locktime = options.locktime;
@@ -129,7 +130,7 @@ MinerBlock.prototype._init = function _init() {
   block.version = this.version;
   block.prevBlock = this.tip.hash;
   block.merkleRoot = encoding.NULL_HASH;
-  block.ts = Math.max(this.network.now(), this.tip.ts + 1);
+  block.ts = this.ts;
   block.bits = this.bits;
   block.nonce = 0;