diff --git a/README.md b/README.md
index 932ce86..d5dc8fc 100644
--- a/README.md
+++ b/README.md
@@ -225,6 +225,8 @@ ethereumjs.run({ network: 'rinkeby', syncmode: 'light', bootnodes: '/ip4/127.0.0
 
 That's it! Now, you should start seeing headers being downloaded to the local storage of your browser. Since IndexDB is being used, even if you close and re-open the browser window, the headers you'll already downloaded will be saved.
 
+![EthereumJS Client Libp2p Browser Syncing](./browser_sync.png?raw=true)
+
 ## Design
 
 **Goals**
diff --git a/browser_sync.png b/browser_sync.png
new file mode 100644
index 0000000..e782229
Binary files /dev/null and b/browser_sync.png differ
diff --git a/lib/service/ethereumservice.js b/lib/service/ethereumservice.js
index d9c8eaa..7d9129a 100644
--- a/lib/service/ethereumservice.js
+++ b/lib/service/ethereumservice.js
@@ -37,6 +37,7 @@ class EthereumService extends Service {
 
     this.flow = new FlowControl(options)
     this.chain = options.chain || new Chain(options)
+    this.common = options.common
     this.minPeers = options.minPeers
     this.interval = options.interval
     this.timeout = options.timeout
diff --git a/lib/service/fastethereumservice.js b/lib/service/fastethereumservice.js
index 0051cab..aa907da 100644
--- a/lib/service/fastethereumservice.js
+++ b/lib/service/fastethereumservice.js
@@ -39,6 +39,7 @@ class FastEthereumService extends EthereumService {
       logger: this.logger,
       pool: this.pool,
       chain: this.chain,
+      common: this.common,
       minPeers: this.minPeers,
       interval: this.interval
     })
diff --git a/lib/service/lightethereumservice.js b/lib/service/lightethereumservice.js
index 9c3c6c6..4baca1b 100644
--- a/lib/service/lightethereumservice.js
+++ b/lib/service/lightethereumservice.js
@@ -31,6 +31,7 @@ class LightEthereumService extends EthereumService {
       logger: this.logger,
       pool: this.pool,
       chain: this.chain,
+      common: this.common,
       minPeers: this.minPeers,
       flow: this.flow,
       interval: this.interval
diff --git a/lib/sync/fastsync.js b/lib/sync/fastsync.js
index 4c5346e..e34577b 100644
--- a/lib/sync/fastsync.js
+++ b/lib/sync/fastsync.js
@@ -75,6 +75,7 @@ class FastSynchronizer extends Synchronizer {
     this.blockFetcher = new BlockFetcher({
       pool: this.pool,
       chain: this.chain,
+      common: this.common,
       logger: this.logger,
       interval: this.interval,
       first,
diff --git a/lib/sync/fetcher/blockfetcher.js b/lib/sync/fetcher/blockfetcher.js
index c26fa4f..afbc708 100644
--- a/lib/sync/fetcher/blockfetcher.js
+++ b/lib/sync/fetcher/blockfetcher.js
@@ -64,7 +64,7 @@ class BlockFetcher extends Fetcher {
     let { first, count } = task
     const headers = await peer.eth.getBlockHeaders({ block: first, max: count })
     const bodies = await peer.eth.getBlockBodies(headers.map(h => h.hash()))
-    const blocks = bodies.map((body, i) => new Block([headers[i]].concat(body)))
+    const blocks = bodies.map((body, i) => new Block([headers[i]].concat(body), { common: this.common }))
     return { blocks }
   }
 
diff --git a/lib/sync/fetcher/fetcher.js b/lib/sync/fetcher/fetcher.js
index d9683db..09f1116 100644
--- a/lib/sync/fetcher/fetcher.js
+++ b/lib/sync/fetcher/fetcher.js
@@ -2,9 +2,11 @@
 
 const { Readable, Writable } = require('stream')
 const Heap = require('qheap')
+const Common = require('ethereumjs-common').default
 const { defaultLogger } = require('../../logging')
 
 const defaultOptions = {
+  common: new Common('mainnet', 'chainstart'),
   logger: defaultLogger,
   timeout: 5000,
   interval: 1000,
@@ -24,6 +26,7 @@ class Fetcher extends Readable {
   /**
    * Create new fetcher
    * @param {Object}   options constructor parameters
+   * @param {Common}   options.common common chain config
    * @param {PeerPool} options.pool peer pool
    * @param {number}   [options.timeout] fetch task timeout
    * @param {number}   [options.banTime] how long to ban misbehaving peers
@@ -36,6 +39,7 @@ class Fetcher extends Readable {
     super({ ...options, objectMode: true })
     options = { ...defaultOptions, ...options }
 
+    this.common = options.common
     this.pool = options.pool
     this.logger = options.logger
     this.timeout = options.timeout
diff --git a/lib/sync/lightsync.js b/lib/sync/lightsync.js
index b53d86c..506bbe7 100644
--- a/lib/sync/lightsync.js
+++ b/lib/sync/lightsync.js
@@ -62,6 +62,7 @@ class LightSynchronizer extends Synchronizer {
     this.headerFetcher = new HeaderFetcher({
       pool: this.pool,
       chain: this.chain,
+      common: this.common,
       flow: this.flow,
       logger: this.logger,
       interval: this.interval,
diff --git a/lib/sync/sync.js b/lib/sync/sync.js
index 8df89b2..54ea3da 100644
--- a/lib/sync/sync.js
+++ b/lib/sync/sync.js
@@ -1,9 +1,11 @@
 'use strict'
 
+const Common = require('ethereumjs-common').default
 const EventEmitter = require('events')
 const { defaultLogger } = require('../logging')
 
 const defaultOptions = {
+  common: new Common('mainnet', 'chainstart'),
   logger: defaultLogger,
   interval: 1000,
   minPeers: 3
@@ -19,6 +21,7 @@ class Synchronizer extends EventEmitter {
    * @param {Object}      options constructor parameters
    * @param {PeerPool}    options.pool peer pool
    * @param {Chain}       options.chain blockchain
+   * @param {Common}      options.common common chain config
    * @param {FlowControl} options.flow flow control manager
    * @param {number}      [options.minPeers=3] number of peers needed before syncing
    * @param {number}      [options.interval] refresh interval
@@ -31,6 +34,7 @@ class Synchronizer extends EventEmitter {
     this.logger = options.logger
     this.pool = options.pool
     this.chain = options.chain
+    this.common = options.common
     this.flow = options.flow
     this.minPeers = options.minPeers
     this.interval = options.interval