diff --git a/lib/bcoin/block.js b/lib/bcoin/block.js
index f73794a5..321a6a46 100644
--- a/lib/bcoin/block.js
+++ b/lib/bcoin/block.js
@@ -340,7 +340,7 @@ Block.reward = function reward(height) {
   if (halvings >= 64)
     return new bn(0);
 
-  reward = utils.satoshi('50.0');
+  reward = new bn(50).mul(constants.coin);
   reward.iushrn(halvings);
 
   return reward;
@@ -354,9 +354,7 @@ Block.prototype._getReward = function _getReward() {
 
   base = Block.reward(this.height);
 
-  if (this.subtype !== 'block'
-      || this.txs.length === 0
-      || !this.txs[0].isCoinbase()) {
+  if (this.subtype !== 'block' || this.height === -1) {
     return this._reward = {
       fee: new bn(0),
       reward: base,
@@ -369,14 +367,6 @@ Block.prototype._getReward = function _getReward() {
     return total;
   }, new bn(0));
 
-  // If height is not accurate, artificially increase
-  // the reward era until base is smaller than the reward.
-  height = 0;
-  while (base.cmp(reward) > 0) {
-    base = Block.reward(height);
-    height += constants.halvingInterval;
-  }
-
   fee = reward.sub(base);
 
   return this._reward = {
diff --git a/scripts/gen.js b/scripts/gen.js
new file mode 100644
index 00000000..178bf016
--- /dev/null
+++ b/scripts/gen.js
@@ -0,0 +1,111 @@
+var bcoin = require('bcoin');
+var constants = bcoin.protocol.constants;
+var utils = bcoin.utils;
+var bn = bcoin.bn;
+
+function createGenesisBlock(options) {
+  var parser = new bcoin.protocol.parser();
+  var tx, block;
+
+  if (!options.flags) {
+    options.flags = new Buffer(
+      'The Times 03/Jan/2009 Chancellor on brink of second bailout for banks',
+      'ascii');
+  }
+
+  if (!options.script) {
+    options.script = [
+      new Buffer('04678afdb0fe5548271967f1a67130b7105cd6a828e039'
+        + '09a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c3'
+        + '84df7ba0b8d578a4c702b6bf11d5f', 'hex'),
+      'checksig'
+    ];
+  }
+
+  if (!options.reward)
+    options.reward = new bn(50).mul(constants.coin);
+
+  tx = {
+    version: 1,
+    inputs: [{
+      prevout: {
+        hash: utils.toHex(constants.zeroHash),
+        index: 0xffffffff
+      },
+      script: [
+        new bn(486604799, 'le').toBuffer(),
+        new bn(4, 'le').toBuffer(),
+        options.flags
+      ],
+      sequence: 0xffffffff
+    }],
+    outputs: [{
+      value: options.reward,
+      script: options.script
+    }],
+    locktime: 0
+  };
+
+  tx._raw = bcoin.protocol.framer.tx(tx);
+
+  block = {
+    version: options.version,
+    prevBlock: utils.toHex(constants.zeroHash),
+    merkleRoot: utils.toHex(utils.dsha256(tx._raw)),
+    ts: options.ts,
+    bits: options.bits,
+    nonce: options.nonce,
+    txs: [tx]
+  };
+
+  block._raw = bcoin.protocol.framer.block(block);
+
+  block = parser.parseBlock(block._raw);
+
+  block._hash = utils.dsha256(block._raw.slice(0, 80));
+  block.hash = utils.toHex(block._hash);
+  block.network = true;
+  block.height = 0;
+
+  tx = block.txs[0];
+  tx.network = true;
+  tx.height = 0;
+  tx.ts = block.ts;
+  tx._hash = block.merkleRoot;
+  tx.hash = utils.toHex(tx._hash);
+
+  return block;
+}
+
+var main = createGenesisBlock({
+  version: 1,
+  ts: 1231006505,
+  bits: 486604799,
+  nonce: 2083236893
+});
+
+var testnet = createGenesisBlock({
+  version: 1,
+  ts: 1296688602,
+  bits: 486604799,
+  nonce: 414098458
+});
+
+var regtest = createGenesisBlock({
+  version: 1,
+  ts: 1296688602,
+  bits: 545259519,
+  nonce: 2
+});
+
+utils.print(main);
+utils.print(testnet);
+utils.print(regtest);
+utils.print('main hash: %s', main.hash);
+utils.print('main raw: %s', utils.toHex(main._raw));
+utils.print('');
+utils.print('testnet hash: %s', testnet.hash);
+utils.print('testnet raw: %s', utils.toHex(testnet._raw));
+utils.print('');
+utils.print('regtest hash: %s', regtest.hash);
+utils.print('regtest raw: %s', utils.toHex(regtest._raw));