diff --git a/libraries/Bridge/Bridge.cpp b/libraries/Bridge/Bridge.cpp
index a653b12..928479c 100644
--- a/libraries/Bridge/Bridge.cpp
+++ b/libraries/Bridge/Bridge.cpp
@@ -55,11 +55,12 @@ void BridgeClass::begin() {
   transfer(cmd, 2);
 }
 
-uint8_t BridgeClass::runCommand(String &command) {
+uint8_t BridgeClass::runCommand(String &command, uint8_t &err) {
   uint8_t cmd[] = {'R'};
-  uint8_t res[1];
-  transfer(cmd, 1, (uint8_t*)command.c_str(), command.length(), res, 1);
-  return res[0];
+  uint8_t res[2];
+  transfer(cmd, 1, (uint8_t*)command.c_str(), command.length(), res, 2);
+  err = res[0];
+  return res[1];
 }
 
 bool BridgeClass::commandIsRunning(uint8_t handle) {
diff --git a/libraries/Bridge/Bridge.h b/libraries/Bridge/Bridge.h
index 6043e15..6e54bbd 100644
--- a/libraries/Bridge/Bridge.h
+++ b/libraries/Bridge/Bridge.h
@@ -28,7 +28,7 @@ public:
   void begin();
   
   // Methods to handle processes on the linux side
-  uint8_t runCommand(String &command);
+  uint8_t runCommand(String &command, uint8_t &err);
   bool commandIsRunning(uint8_t handle);
   unsigned int commandExitValue(uint8_t handle);
   void cleanCommand(uint8_t handle);
diff --git a/libraries/Bridge/Process.cpp b/libraries/Bridge/Process.cpp
index 7265119..59fe2b7 100644
--- a/libraries/Bridge/Process.cpp
+++ b/libraries/Bridge/Process.cpp
@@ -85,11 +85,13 @@ void Process::addParameter(String &param) {
 }
 
 void Process::runAsynchronously() {
-  handle = bridge.runCommand(*cmdline);
+  uint8_t err;
+  handle = bridge.runCommand(*cmdline, err);
   delete cmdline;
   cmdline = NULL;
   
-  started = true;
+  if (err==0)
+    started = true;
 }
 
 boolean Process::running() {
diff --git a/libraries/Bridge/Process.h b/libraries/Bridge/Process.h
index b48e046..ac22b15 100644
--- a/libraries/Bridge/Process.h
+++ b/libraries/Bridge/Process.h
@@ -39,6 +39,8 @@ public:
   unsigned int exitValue();
   void close();
 
+  operator bool () { return started; }
+
   // Stream methods 
   // (read from process stdout)
   int available();