diff --git a/lib/cmds/blockchain/blockchain.js b/lib/cmds/blockchain/blockchain.js
index 305e1c025..767f04c07 100644
--- a/lib/cmds/blockchain/blockchain.js
+++ b/lib/cmds/blockchain/blockchain.js
@@ -44,8 +44,7 @@ var Blockchain = function(options) {
     wsApi: (this.blockchainConfig.wsApi || ['eth', 'web3', 'net', 'shh']),
     vmdebug: this.blockchainConfig.vmdebug || false,
     targetGasLimit: this.blockchainConfig.targetGasLimit || false,
-    light: this.blockchainConfig.light || false,
-    fast: this.blockchainConfig.fast || false,
+    syncMode: this.blockchainConfig.syncMode,
     verbosity: this.blockchainConfig.verbosity
   };
 
diff --git a/lib/cmds/blockchain/geth_commands.js b/lib/cmds/blockchain/geth_commands.js
index bf94cf228..e6ef57188 100644
--- a/lib/cmds/blockchain/geth_commands.js
+++ b/lib/cmds/blockchain/geth_commands.js
@@ -20,12 +20,8 @@ class GethCommands {
       cmd.push(`--datadir=${config.datadir}`);
     }
 
-    if (config.light) {
-      cmd.push("--light");
-    }
-
-    if (config.fast) {
-      cmd.push("--fast");
+    if (config.syncMode) {
+      cmd.push("--syncmode=" + config.syncMode);
     }
 
     if (config.account && config.account.password) {
diff --git a/test_apps/contracts_app/blockchain.json b/test_apps/contracts_app/blockchain.json
index 9770fd6c7..80394f5f1 100644
--- a/test_apps/contracts_app/blockchain.json
+++ b/test_apps/contracts_app/blockchain.json
@@ -26,6 +26,7 @@
     "networkType": "testnet",
     "rpcHost": "localhost",
     "rpcPort": 8545,
+    "syncMode": "fast",
     "account": {
       "password": "config/ropsten/password"
     }
@@ -34,6 +35,7 @@
     "networkType": "rinkeby",
     "rpcHost": "localhost",
     "rpcPort": 8545,
+    "syncMode": "fast",
     "account": {
       "password": "config/rinkeby/password"
     }
diff --git a/test_apps/test_app/config/blockchain.json b/test_apps/test_app/config/blockchain.json
index 52543588a..cf136e8d4 100644
--- a/test_apps/test_app/config/blockchain.json
+++ b/test_apps/test_app/config/blockchain.json
@@ -26,6 +26,7 @@
     "networkType": "testnet",
     "rpcHost": "localhost",
     "rpcPort": 8545,
+    "syncMode": "fast",
     "account": {
       "password": "config/ropsten/password"
     }
@@ -34,6 +35,7 @@
     "networkType": "rinkeby",
     "rpcHost": "localhost",
     "rpcPort": 8545,
+    "syncMode": "fast",
     "account": {
       "password": "config/rinkeby/password"
     }