diff --git a/lib/blockchain/chain.js b/lib/blockchain/chain.js
index a4674eeb..7f100868 100644
--- a/lib/blockchain/chain.js
+++ b/lib/blockchain/chain.js
@@ -2238,7 +2238,7 @@ Chain.prototype.getProofTime = function getProofTime(to, from) {
   const pow = this.network.pow;
   let sign, work;
 
-  if (to.chainwork.cmp(from.chainwork) > 0) {
+  if (to.chainwork.gt(from.chainwork)) {
     work = to.chainwork.sub(from.chainwork);
     sign = 1;
   } else {
@@ -2343,7 +2343,7 @@ Chain.prototype.retarget = function retarget(prev, first) {
   target.imuln(actualTimespan);
   target.idivn(targetTimespan);
 
-  if (target.cmp(pow.limit) > 0)
+  if (target.gt(pow.limit))
     return pow.bits;
 
   return consensus.toCompact(target);
diff --git a/lib/blockchain/chainentry.js b/lib/blockchain/chainentry.js
index de9fece0..d621869b 100644
--- a/lib/blockchain/chainentry.js
+++ b/lib/blockchain/chainentry.js
@@ -117,7 +117,7 @@ ChainEntry.fromOptions = function fromOptions(options, prev) {
 ChainEntry.prototype.getProof = function getProof() {
   const target = consensus.fromCompact(this.bits);
 
-  if (target.isNeg() || target.cmpn(0) === 0)
+  if (target.isNeg() || target.isZero())
     return new BN(0);
 
   return ChainEntry.MAX_CHAINWORK.div(target.iaddn(1));
@@ -144,7 +144,7 @@ ChainEntry.prototype.getChainwork = function getChainwork(prev) {
  */
 
 ChainEntry.prototype.isGenesis = function isGenesis() {
-  return this.prevBlock === encoding.NULL_HASH;
+  return this.height === 0;
 };
 
 /**
@@ -154,10 +154,11 @@ ChainEntry.prototype.isGenesis = function isGenesis() {
  */
 
 ChainEntry.prototype.hasUnknown = function hasUnknown(network) {
-  const bits = this.version & consensus.VERSION_TOP_MASK;
-  const topBits = consensus.VERSION_TOP_BITS;
+  const TOP_MASK = consensus.VERSION_TOP_MASK;
+  const TOP_BITS = consensus.VERSION_TOP_BITS;
+  const bits = (this.version & TOP_MASK) >>> 0;
 
-  if ((bits >>> 0) !== topBits)
+  if (bits !== TOP_BITS)
     return false;
 
   return (this.version & network.unknownBits) !== 0;
diff --git a/lib/mining/common.js b/lib/mining/common.js
index 2740ace6..3b43c7f6 100644
--- a/lib/mining/common.js
+++ b/lib/mining/common.js
@@ -132,7 +132,7 @@ common.getTarget = function getTarget(bits) {
   if (target.isNeg())
     throw new Error('Target is negative.');
 
-  if (target.cmpn(0) === 0)
+  if (target.isZero())
     throw new Error('Target is zero.');
 
   return target.toArrayLike(Buffer, 'le', 32);
@@ -147,7 +147,7 @@ common.getTarget = function getTarget(bits) {
 common.getBits = function getBits(data) {
   const target = new BN(data, 'le');
 
-  if (target.cmpn(0) === 0)
+  if (target.isZero())
     throw new Error('Target is zero.');
 
   return consensus.toCompact(target);
diff --git a/lib/protocol/consensus.js b/lib/protocol/consensus.js
index 1cf8bc34..74e5132a 100644
--- a/lib/protocol/consensus.js
+++ b/lib/protocol/consensus.js
@@ -226,14 +226,15 @@ exports.BIP16_TIME = 1333238400;
  */
 
 exports.fromCompact = function fromCompact(compact) {
-  const exponent = compact >>> 24;
-  const negative = (compact >>> 23) & 1;
-  let mantissa = compact & 0x7fffff;
-  let num;
-
   if (compact === 0)
     return new BN(0);
 
+  const exponent = compact >>> 24;
+  const negative = (compact >>> 23) & 1;
+
+  let mantissa = compact & 0x7fffff;
+  let num;
+
   if (exponent <= 3) {
     mantissa >>>= 8 * (3 - exponent);
     num = new BN(mantissa);
@@ -256,12 +257,11 @@ exports.fromCompact = function fromCompact(compact) {
  */
 
 exports.toCompact = function toCompact(num) {
-  let mantissa, exponent, compact;
-
-  if (num.cmpn(0) === 0)
+  if (num.isZero())
     return 0;
 
-  exponent = num.byteLength();
+  let exponent = num.byteLength();
+  let mantissa;
 
   if (exponent <= 3) {
     mantissa = num.toNumber();
@@ -275,7 +275,7 @@ exports.toCompact = function toCompact(num) {
     exponent++;
   }
 
-  compact = (exponent << 24) | mantissa;
+  let compact = (exponent << 24) | mantissa;
 
   if (num.isNeg())
     compact |= 0x800000;
@@ -295,12 +295,12 @@ exports.toCompact = function toCompact(num) {
 exports.verifyPOW = function verifyPOW(hash, bits) {
   const target = exports.fromCompact(bits);
 
-  if (target.isNeg() || target.cmpn(0) === 0)
+  if (target.isNeg() || target.isZero())
     return false;
 
-  hash = new BN(hash, 'le');
+  const num = new BN(hash, 'le');
 
-  if (hash.cmp(target) > 0)
+  if (num.gt(target))
     return false;
 
   return true;
@@ -313,10 +313,10 @@ exports.verifyPOW = function verifyPOW(hash, bits) {
  */
 
 exports.getReward = function getReward(height, interval) {
-  const halvings = Math.floor(height / interval);
-
   assert(height >= 0, 'Bad height for reward.');
 
+  const halvings = Math.floor(height / interval);
+
   // BIP 42 (well, our own version of it,
   // since we can only handle 32 bit shifts).
   // https://github.com/bitcoin/bips/blob/master/bip-0042.mediawiki
@@ -341,8 +341,9 @@ exports.getReward = function getReward(height, interval) {
  */
 
 exports.hasBit = function hasBit(version, bit) {
-  const bits = version & exports.VERSION_TOP_MASK;
-  const topBits = exports.VERSION_TOP_BITS;
+  const TOP_MASK = exports.VERSION_TOP_MASK;
+  const TOP_BITS = exports.VERSION_TOP_BITS;
+  const bits = (version & TOP_MASK) >>> 0;
   const mask = 1 << bit;
-  return (bits >>> 0) === topBits && (version & mask) !== 0;
+  return bits === TOP_BITS && (version & mask) !== 0;
 };
diff --git a/lib/utils/gcs.js b/lib/utils/gcs.js
index a0881190..29501171 100644
--- a/lib/utils/gcs.js
+++ b/lib/utils/gcs.js
@@ -507,7 +507,7 @@ BitReader.prototype.readBits64 = function readBits64(count) {
  */
 
 function compare(a, b) {
-  return a.cmp(b) < 0 ? -1 : 1;
+  return a.lt(b) ? -1 : 1;
 }
 
 function siphash24(data, key) {
diff --git a/test/chain-test.js b/test/chain-test.js
index 8cfc2ceb..2b58ae60 100644
--- a/test/chain-test.js
+++ b/test/chain-test.js
@@ -197,7 +197,7 @@ describe('Chain', function() {
 
     assert(forked);
     assert.strictEqual(chain.tip.hash, block.hash('hex'));
-    assert(chain.tip.chainwork.cmp(tip1.chainwork) > 0);
+    assert(chain.tip.chainwork.gt(tip1.chainwork));
   });
 
   it('should have correct chain value', () => {
diff --git a/test/node-test.js b/test/node-test.js
index e400f4d8..73d0021c 100644
--- a/test/node-test.js
+++ b/test/node-test.js
@@ -163,7 +163,7 @@ describe('Node', function() {
 
     assert(forked);
     assert.strictEqual(chain.tip.hash, block.hash('hex'));
-    assert(chain.tip.chainwork.cmp(tip1.chainwork) > 0);
+    assert(chain.tip.chainwork.gt(tip1.chainwork));
   });
 
   it('should have correct chain value', () => {