diff --git a/lib/bcoin/abstractblock.js b/lib/bcoin/abstractblock.js
index b4bb15e8..9867bc72 100644
--- a/lib/bcoin/abstractblock.js
+++ b/lib/bcoin/abstractblock.js
@@ -7,6 +7,7 @@
 var bcoin = require('../bcoin');
 var utils = require('./utils');
 var network = bcoin.protocol.network;
+var BufferWriter = require('./writer');
 
 /**
  * AbstractBlock
@@ -50,20 +51,21 @@ AbstractBlock.prototype.hash = function hash(enc) {
 };
 
 AbstractBlock.prototype.abbr = function abbr() {
-  var res;
+  var p;
 
   if (this._raw)
     return this._raw.slice(0, 80);
 
-  res = new Buffer(80);
-  utils.write32(res, this.version, 0);
-  utils.copy(new Buffer(this.prevBlock, 'hex'), res, 4);
-  utils.copy(new Buffer(this.merkleRoot, 'hex'), res, 36);
-  utils.writeU32(res, this.ts, 68);
-  utils.writeU32(res, this.bits, 72);
-  utils.writeU32(res, this.nonce, 76);
+  p = new BufferWriter();
 
-  return res;
+  p.write32(this.version);
+  p.writeHash(this.prevBlock);
+  p.writeHash(this.merkleRoot);
+  p.writeU32(this.ts);
+  p.writeU32(this.bits);
+  p.writeU32(this.nonce);
+
+  return p.render();
 };
 
 AbstractBlock.prototype.getSize = function getSize() {
diff --git a/lib/bcoin/block.js b/lib/bcoin/block.js
index f3949b86..c3c112bd 100644
--- a/lib/bcoin/block.js
+++ b/lib/bcoin/block.js
@@ -341,60 +341,46 @@ Block.fromRaw = function fromRaw(data, enc, type) {
 };
 
 Block.prototype.toCompact = function toCompact() {
-  var block = this.abbr();
+  var p = new BufferWriter();
   var height = this.height;
-  var off = 0;
-  var buf;
-
-  buf = new Buffer(
-    block.length + 4
-    + utils.sizeIntv(this.txs.length)
-    + this.txs.length * 32);
 
   if (height === -1)
     height = 0x7fffffff;
 
-  off += utils.copy(block, buf, off);
-  off += utils.writeU32(buf, height, off);
+  p.writeBytes(this.abbr());
+  p.writeU32(height);
+  p.writeIntv(this.txs.length);
 
-  off += utils.writeIntv(buf, this.txs.length, off);
   this.txs.forEach(function(tx) {
-    off += utils.copy(tx.hash(), buf, off);
+    p.writeBytes(tx.hash());
   });
 
-  return buf;
+  return p.render();
 };
 
 Block.fromCompact = function fromCompact(buf) {
-  var off = 0;
+  var p = new BufferReader(buf);
   var hashes = [];
+  var version = p.read32();
+  var prevBlock = p.readHash('hex');
+  var merkleRoot = p.readHash('hex');
+  var ts = p.readU32();
+  var bits = p.readU32();
+  var nonce = p.readU32();
+  var height = p.readU32();
+  var txCount = p.readIntv();
   var i;
 
-  var version = utils.read32(buf, 0);
-  var prevBlock = buf.slice(4, 36);
-  var merkleRoot = buf.slice(36, 68);
-  var ts = utils.readU32(buf, 68);
-  var bits = utils.readU32(buf, 72);
-  var nonce = utils.readU32(buf, 76);
-  var height = utils.readU32(buf, 80);
-  var txCount = utils.readIntv(buf, 84);
-  off = txCount.off;
-  txCount = txCount.r;
-
-  for (i = 0; i < txCount; i++) {
-    if (off + 32 > buf.length)
-      throw new Error('Bad TX count.');
-    hashes.push(utils.toHex(buf.slice(off, off + 32)));
-    off += 32;
-  }
+  for (i = 0; i < txCount; i++)
+    hashes.push(p.readHash('hex'));
 
   if (height === 0x7fffffff)
     height = -1;
 
   return {
     version: version,
-    prevBlock: utils.toHex(prevBlock),
-    merkleRoot: utils.toHex(merkleRoot),
+    prevBlock: prevBlock,
+    merkleRoot: merkleRoot,
     ts: ts,
     bits: bits,
     nonce: nonce,
diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index aa0d0650..da3f5fac 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -12,6 +12,7 @@ var constants = bcoin.protocol.constants;
 var network = bcoin.protocol.network;
 var utils = require('./utils');
 var assert = utils.assert;
+var BufferReader = require('./reader');
 
 /**
  * Chain
@@ -254,6 +255,21 @@ Chain.prototype._preload = function _preload(callback) {
 
   utils.debug('Loading %s', url);
 
+  function parseHeader(buf) {
+    var p = new BufferReader(buf);
+    var hash = utils.dsha256(buf.slice(0, 80));
+
+    return {
+      hash: utils.toHex(hash),
+      version: p.read32(),
+      prevBlock: p.readHash('hex'),
+      merkleRoot: p.readHash('hex'),
+      ts: p.readU32(),
+      bits: p.readU32(),
+      nonce: p.readU32()
+    };
+  }
+
   this.db.getChainHeight(function(err, chainHeight) {
     if (err)
       return callback(err);
@@ -305,15 +321,19 @@ Chain.prototype._preload = function _preload(callback) {
         return;
 
       blocks.forEach(function(data) {
-        var entry = bcoin.chainblock.fromRaw(self, data);
-        var block, start;
+        var block, entry, start;
 
-        entry.height = height;
+        data = parseHeader(data);
+        data.height = height;
 
-        block = bcoin.headers(entry);
+        // Make sure the genesis block is correct.
+        if (data.height === 0 && data.hash !== network.genesis.hash) {
+          stream.destroy();
+          return callback(new Error('Bad genesis block.'), 0);
+        }
 
         // Do some paranoid checks.
-        if (lastEntry && entry.prevBlock !== lastEntry.hash) {
+        if (lastEntry && data.prevBlock !== lastEntry.hash) {
           start = Math.max(0, height - 2);
           stream.destroy();
           return self.reset(start, function(err) {
@@ -323,6 +343,9 @@ Chain.prototype._preload = function _preload(callback) {
           });
         }
 
+        // Create headers object for validation.
+        block = new bcoin.headers(data);
+
         // Verify the block headers. We don't want to
         // trust an external centralized source completely.
         if (!block.verifyHeaders()) {
@@ -335,31 +358,23 @@ Chain.prototype._preload = function _preload(callback) {
           });
         }
 
-        // Calculate chainwork.
-        delete entry.chainwork;
-        entry.chainwork = entry.getChainwork(lastEntry);
-
-        lastEntry = entry;
-
-        // Make sure the genesis block is correct.
-        if (height === 0 && entry.hash !== network.genesis.hash) {
-          stream.destroy();
-          return callback(new Error('Bad genesis block.'), 0);
-        }
+        // Create a chain entry.
+        entry = new bcoin.chainblock(self, data, lastEntry);
 
         // Filthy hack to avoid writing
         // redundant blocks to disk!
-        if (height <= chainHeight) {
+        if (entry.height <= chainHeight) {
           self.db.addCache(entry);
           // self.db.bloom(entry.hash, 'hex');
         } else {
           self.db.save(entry);
         }
 
-        height++;
-
         if ((height + 1) % 50000 === 0)
           utils.debug('Received %d headers from electrum.org.', height + 1);
+
+        lastEntry = entry;
+        height++;
       });
     });
 
diff --git a/lib/bcoin/chainblock.js b/lib/bcoin/chainblock.js
index ed791c2a..365260be 100644
--- a/lib/bcoin/chainblock.js
+++ b/lib/bcoin/chainblock.js
@@ -10,6 +10,8 @@ var constants = bcoin.protocol.constants;
 var network = bcoin.protocol.network;
 var utils = require('./utils');
 var assert = utils.assert;
+var BufferWriter = require('./writer');
+var BufferReader = require('./reader');
 
 /**
  * ChainBlock
@@ -241,31 +243,34 @@ ChainBlock.prototype.getMedianTimeAsync = function getMedianTimeAsync(callback)
 };
 
 ChainBlock.prototype.toRaw = function toRaw() {
-  var res = new Buffer(116);
+  var p = new BufferWriter();
 
-  utils.write32(res, this.version, 0);
-  utils.copy(new Buffer(this.prevBlock, 'hex'), res, 4);
-  utils.copy(new Buffer(this.merkleRoot, 'hex'), res, 36);
-  utils.writeU32(res, this.ts, 68);
-  utils.writeU32(res, this.bits, 72);
-  utils.writeU32(res, this.nonce, 76);
-  utils.writeU32(res, this.height, 80);
-  utils.copy(new Buffer(this.chainwork.toArray('le', 32)), res, 84);
+  p.write32(this.version);
+  p.writeHash(this.prevBlock);
+  p.writeHash(this.merkleRoot);
+  p.writeU32(this.ts);
+  p.writeU32(this.bits);
+  p.writeU32(this.nonce);
+  p.writeU32(this.height);
+  p.writeBytes(new Buffer(this.chainwork.toArray('le', 32)));
 
-  return res;
+  return p.render();
 };
 
-ChainBlock.fromRaw = function fromRaw(chain, p) {
+ChainBlock.fromRaw = function fromRaw(chain, buf) {
+  var p = new BufferReader(buf);
+  var hash = utils.dsha256(buf.slice(0, 80));
+
   return new ChainBlock(chain, {
-    hash: utils.toHex(utils.dsha256(p.slice(0, 80))),
-    version: utils.read32(p, 0),
-    prevBlock: utils.toHex(p.slice(4, 36)),
-    merkleRoot: utils.toHex(p.slice(36, 68)),
-    ts: utils.readU32(p, 68),
-    bits: utils.readU32(p, 72),
-    nonce: utils.readU32(p, 76),
-    height: utils.readU32(p, 80),
-    chainwork: new bn(p.slice(84, 116), 'le')
+    hash: utils.toHex(hash),
+    version: p.read32(),
+    prevBlock: p.readHash('hex'),
+    merkleRoot: p.readHash('hex'),
+    ts: p.readU32(),
+    bits: p.readU32(),
+    nonce: p.readU32(),
+    height: p.readU32(),
+    chainwork: new bn(p.readBytes(32), 'le')
   });
 };
 
diff --git a/lib/bcoin/reader.js b/lib/bcoin/reader.js
index fbccced1..e74d32a3 100644
--- a/lib/bcoin/reader.js
+++ b/lib/bcoin/reader.js
@@ -172,7 +172,9 @@ BufferReader.prototype.readString = function readString(enc, size) {
   return ret;
 };
 
-BufferReader.prototype.readHash = function readHash() {
+BufferReader.prototype.readHash = function readHash(enc) {
+  if (enc)
+    return this.readBytes(32).toString(enc);
   return this.readBytes(32);
 };
 
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index 15ec54a3..57e7d040 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -1182,6 +1182,52 @@ utils.writeU64BE = function writeU64BE(dst, num, off) {
   return 8;
 };
 
+utils.writeU256 = function writeU256(dst, num, off) {
+  var i;
+
+  if (!(num instanceof bn))
+    num = new bn(+num);
+
+  off = off >>> 0;
+
+  // We shouldn't think of
+  // this as negative.
+  if (num.isNeg())
+    num = num.neg();
+
+  num = num.toArray('le', 32);
+
+  assert.equal(num.length, 32);
+
+  for (i = 0; i < num.length; i++)
+    dst[off++] = num[i] & 0xff;
+
+  return 32;
+};
+
+utils.writeU256BE = function writeU256BE(dst, num, off) {
+  var i;
+
+  if (!(num instanceof bn))
+    num = new bn(+num);
+
+  off = off >>> 0;
+
+  // We shouldn't think of
+  // this as negative.
+  if (num.isNeg())
+    num = num.neg();
+
+  num = num.toArray('be', 32);
+
+  assert.equal(num.length, 32);
+
+  for (i = 0; i < num.length; i++)
+    dst[off++] = num[i] & 0xff;
+
+  return 32;
+};
+
 utils.write8 = function write8(dst, num, off) {
   num = +num;
   off = off >>> 0;