diff --git a/ethminer/MinerAux.h b/ethminer/MinerAux.h
index 476c810c2..65311b019 100644
--- a/ethminer/MinerAux.h
+++ b/ethminer/MinerAux.h
@@ -97,11 +97,11 @@ public:
 		if ((arg == "-F" || arg == "--farm") && i + 1 < argc)
 		{
 			mode = OperationMode::Farm;
-			farmURL = argv[++i];
+			m_farmURL = argv[++i];
 		}
 		else if (arg == "--farm-recheck" && i + 1 < argc)
 			try {
-				farmRecheckPeriod = stol(argv[++i]);
+				m_farmRecheckPeriod = stol(argv[++i]);
 			}
 			catch (...)
 			{
@@ -110,7 +110,7 @@ public:
 			}
 		else if (arg == "--opencl-platform" && i + 1 < argc)
 			try {
-				openclPlatform = stol(argv[++i]);
+				m_openclPlatform = stol(argv[++i]);
 			}
 			catch (...)
 			{
@@ -119,8 +119,8 @@ public:
 			}
 		else if (arg == "--opencl-device" && i + 1 < argc)
 			try {
-				openclDevice = stol(argv[++i]);
-				miningThreads = 1;
+				m_openclDevice = stol(argv[++i]);
+				m_miningThreads = 1;
 			}
 			catch (...)
 			{
@@ -128,17 +128,16 @@ public:
 				throw BadArgument();
 			}
 		else if (arg == "--list-devices")
-		{
-			ProofOfWork::GPUMiner::listDevices();
-			exit(0);
-		}
+			m_shouldListDevices = true;
+		else if (arg == "--allow-opencl-cpu")
+			m_clAllowCPU = true;
 		else if (arg == "--phone-home" && i + 1 < argc)
 		{
 			string m = argv[++i];
 			if (isTrue(m))
-				phoneHome = true;
+				m_phoneHome = true;
 			else if (isFalse(m))
-				phoneHome = false;
+				m_phoneHome = false;
 			else
 			{
 				cerr << "Bad " << arg << " option: " << m << endl;
@@ -147,7 +146,7 @@ public:
 		}
 		else if (arg == "--benchmark-warmup" && i + 1 < argc)
 			try {
-				benchmarkWarmup = stol(argv[++i]);
+				m_benchmarkWarmup = stol(argv[++i]);
 			}
 			catch (...)
 			{
@@ -156,7 +155,7 @@ public:
 			}
 		else if (arg == "--benchmark-trial" && i + 1 < argc)
 			try {
-				benchmarkTrial = stol(argv[++i]);
+				m_benchmarkTrial = stol(argv[++i]);
 			}
 			catch (...)
 			{
@@ -165,7 +164,7 @@ public:
 			}
 		else if (arg == "--benchmark-trials" && i + 1 < argc)
 			try {
-				benchmarkTrials = stol(argv[++i]);
+				m_benchmarkTrials = stol(argv[++i]);
 			}
 			catch (...)
 			{
@@ -175,21 +174,10 @@ public:
 		else if (arg == "-C" || arg == "--cpu")
 			m_minerType = MinerType::CPU;
 		else if (arg == "-G" || arg == "--opencl")
-		{
-			if (!ProofOfWork::GPUMiner::configureGPU())
-			{
-				cout << "No GPU device with sufficient memory was found. Defaulting to CPU" << endl;
-				m_minerType = MinerType::CPU;
-			}
-			else
-			{
-				m_minerType = MinerType::GPU;
-				miningThreads = 1;
-			}
-		}
+			m_minerType = MinerType::GPU;
 		else if (arg == "--no-precompute")
 		{
-			precompute = false;
+			m_precompute = false;
 		}
 		else if ((arg == "-D" || arg == "--create-dag") && i + 1 < argc)
 		{
@@ -197,7 +185,7 @@ public:
 			mode = OperationMode::DAGInit;
 			try
 			{
-				initDAG = stol(m);
+				m_initDAG = stol(m);
 			}
 			catch (...)
 			{
@@ -247,7 +235,7 @@ public:
 		else if ((arg == "-t" || arg == "--mining-threads") && i + 1 < argc)
 		{
 			try {
-				miningThreads = stol(argv[++i]);
+				m_miningThreads = stol(argv[++i]);
 			}
 			catch (...)
 			{
@@ -262,20 +250,29 @@ public:
 
 	void execute()
 	{
+		if (m_shouldListDevices)
+		{
+			ProofOfWork::GPUMiner::listDevices();
+			exit(0);
+		}
+
 		if (m_minerType == MinerType::CPU)
-			ProofOfWork::CPUMiner::setNumInstances(miningThreads);
+			ProofOfWork::CPUMiner::setNumInstances(m_miningThreads);
 		else if (m_minerType == MinerType::GPU)
 		{
-			ProofOfWork::GPUMiner::setDefaultPlatform(openclPlatform);
-			ProofOfWork::GPUMiner::setDefaultDevice(openclDevice);
-			ProofOfWork::GPUMiner::setNumInstances(miningThreads);
+			ProofOfWork::GPUMiner::setNumInstances(m_miningThreads);
+			if (!ProofOfWork::GPUMiner::configureGPU(m_openclPlatform, m_openclDevice, m_clAllowCPU))
+			{
+				cout << "No GPU device with sufficient memory was found. Can't GPU mine. Remove the -G argument" << endl;
+				exit(1);
+			}
 		}
 		if (mode == OperationMode::DAGInit)
-			doInitDAG(initDAG);
+			doInitDAG(m_initDAG);
 		else if (mode == OperationMode::Benchmark)
-			doBenchmark(m_minerType, phoneHome, benchmarkWarmup, benchmarkTrial, benchmarkTrials);
+			doBenchmark(m_minerType, m_phoneHome, m_benchmarkWarmup, m_benchmarkTrial, m_benchmarkTrials);
 		else if (mode == OperationMode::Farm)
-			doFarm(m_minerType, farmURL, farmRecheckPeriod);
+			doFarm(m_minerType, m_farmURL, m_farmRecheckPeriod);
 	}
 
 	static void streamHelp(ostream& _out)
@@ -441,7 +438,7 @@ private:
 						cnote << "Grabbing DAG for" << newSeedHash;
 					if (!(dag = EthashAux::full(newSeedHash, true, [&](unsigned _pc){ cout << "\rCreating DAG. " << _pc << "% done..." << flush; return 0; })))
 						BOOST_THROW_EXCEPTION(DAGCreationFailure());
-					if (precompute)
+					if (m_precompute)
 						EthashAux::computeFull(sha3(newSeedHash), true);
 					if (hh != current.headerHash)
 					{
@@ -490,22 +487,23 @@ private:
 
 	/// Mining options
 	MinerType m_minerType = MinerType::CPU;
-	unsigned openclPlatform = 0;
-	unsigned openclDevice = 0;
-	unsigned miningThreads = UINT_MAX;
-	unsigned dagChunks = 1;
+	unsigned m_openclPlatform = 0;
+	unsigned m_openclDevice = 0;
+	unsigned m_miningThreads = UINT_MAX;
+	bool m_shouldListDevices = false;
+	bool m_clAllowCPU = false;
 
 	/// DAG initialisation param.
-	unsigned initDAG = 0;
+	unsigned m_initDAG = 0;
 
 	/// Benchmarking params
-	bool phoneHome = true;
-	unsigned benchmarkWarmup = 3;
-	unsigned benchmarkTrial = 3;
-	unsigned benchmarkTrials = 5;
+	bool m_phoneHome = true;
+	unsigned m_benchmarkWarmup = 3;
+	unsigned m_benchmarkTrial = 3;
+	unsigned m_benchmarkTrials = 5;
 
 	/// Farm params
-	string farmURL = "http://127.0.0.1:8545";
-	unsigned farmRecheckPeriod = 500;
-	bool precompute = true;
+	string m_farmURL = "http://127.0.0.1:8545";
+	unsigned m_farmRecheckPeriod = 500;
+	bool m_precompute = true;
 };
diff --git a/libethash-cl/ethash_cl_miner.cpp b/libethash-cl/ethash_cl_miner.cpp
index 1a5eaddc3..db08d10c3 100644
--- a/libethash-cl/ethash_cl_miner.cpp
+++ b/libethash-cl/ethash_cl_miner.cpp
@@ -51,6 +51,8 @@ using namespace std;
 
 // TODO: If at any point we can use libdevcore in here then we should switch to using a LogChannel
 #define ETHCL_LOG(_contents) cout << "[OPENCL]:" << _contents << endl
+// Types of OpenCL devices we are interested in
+#define ETHCL_QUERIED_DEVICE_TYPES (CL_DEVICE_TYPE_GPU | CL_DEVICE_TYPE_ACCELERATOR)
 
 static void addDefinition(string& _source, char const* _id, unsigned _value)
 {
@@ -82,9 +84,8 @@ string ethash_cl_miner::platform_info(unsigned _platformId, unsigned _deviceId)
 	}
 
 	// get GPU device of the selected platform
-	vector<cl::Device> devices;
 	unsigned platform_num = min<unsigned>(_platformId, platforms.size() - 1);
-	platforms[platform_num].getDevices(CL_DEVICE_TYPE_ALL, &devices);
+	vector<cl::Device> devices = getDevices(platforms, _platformId);
 	if (devices.empty())
 	{
 		ETHCL_LOG("No OpenCL devices found.");
@@ -99,6 +100,17 @@ string ethash_cl_miner::platform_info(unsigned _platformId, unsigned _deviceId)
 	return "{ \"platform\": \"" + platforms[platform_num].getInfo<CL_PLATFORM_NAME>() + "\", \"device\": \"" + device.getInfo<CL_DEVICE_NAME>() + "\", \"version\": \"" + device_version + "\" }";
 }
 
+std::vector<cl::Device> ethash_cl_miner::getDevices(std::vector<cl::Platform> const& _platforms, unsigned _platformId)
+{
+	vector<cl::Device> devices;
+	unsigned platform_num = min<unsigned>(_platformId, _platforms.size() - 1);
+	_platforms[platform_num].getDevices(
+		s_allowCPU ? CL_DEVICE_TYPE_ALL : ETHCL_QUERIED_DEVICE_TYPES,
+		&devices
+	);
+	return devices;
+}
+
 unsigned ethash_cl_miner::getNumPlatforms()
 {
 	vector<cl::Platform> platforms;
@@ -116,9 +128,7 @@ unsigned ethash_cl_miner::getNumDevices(unsigned _platformId)
 		return 0;
 	}
 
-	vector<cl::Device> devices;
-	unsigned platform_num = min<unsigned>(_platformId, platforms.size() - 1);
-	platforms[platform_num].getDevices(CL_DEVICE_TYPE_ALL, &devices);
+	vector<cl::Device> devices = getDevices(platforms, _platformId);
 	if (devices.empty())
 	{
 		ETHCL_LOG("No OpenCL devices found.");
@@ -127,8 +137,9 @@ unsigned ethash_cl_miner::getNumDevices(unsigned _platformId)
 	return devices.size();
 }
 
-bool ethash_cl_miner::configureGPU()
+bool ethash_cl_miner::configureGPU(bool _allowCPU)
 {
+	s_allowCPU = _allowCPU;
 	return searchForAllDevices([](cl::Device const _device) -> bool
 		{
 			cl_ulong result;
@@ -152,6 +163,8 @@ bool ethash_cl_miner::configureGPU()
 	);
 }
 
+bool ethash_cl_miner::s_allowCPU = false;
+
 bool ethash_cl_miner::searchForAllDevices(function<bool(cl::Device const&)> _callback)
 {
 	vector<cl::Platform> platforms;
@@ -175,8 +188,7 @@ bool ethash_cl_miner::searchForAllDevices(unsigned _platformId, function<bool(cl
 	if (_platformId >= platforms.size())
 		return false;
 
-	vector<cl::Device> devices;
-	platforms[_platformId].getDevices(CL_DEVICE_TYPE_ALL, &devices);
+	vector<cl::Device> devices = getDevices(platforms, _platformId);
 	for (cl::Device const& device: devices)
 		if (_callback(device))
 			return true;
@@ -204,8 +216,7 @@ void ethash_cl_miner::doForAllDevices(unsigned _platformId, function<void(cl::De
 	if (_platformId >= platforms.size())
 		return;
 
-	vector<cl::Device> devices;
-	platforms[_platformId].getDevices(CL_DEVICE_TYPE_ALL, &devices);
+	vector<cl::Device> devices = getDevices(platforms, _platformId);
 	for (cl::Device const& device: devices)
 		_callback(device);
 }
@@ -253,8 +264,7 @@ bool ethash_cl_miner::init(
 		ETHCL_LOG("Using platform: " << platforms[_platformId].getInfo<CL_PLATFORM_NAME>().c_str());
 
 		// get GPU device of the default platform
-		vector<cl::Device> devices;
-		platforms[_platformId].getDevices(CL_DEVICE_TYPE_ALL, &devices);
+		vector<cl::Device> devices = getDevices(platforms, _platformId);
 		if (devices.empty())
 		{
 			ETHCL_LOG("No OpenCL devices found.");
diff --git a/libethash-cl/ethash_cl_miner.h b/libethash-cl/ethash_cl_miner.h
index 4c986053a..44ec7eba9 100644
--- a/libethash-cl/ethash_cl_miner.h
+++ b/libethash-cl/ethash_cl_miner.h
@@ -40,7 +40,7 @@ public:
 	static unsigned getNumDevices(unsigned _platformId = 0);
 	static std::string platform_info(unsigned _platformId = 0, unsigned _deviceId = 0);
 	static void listDevices();
-	static bool configureGPU();
+	static bool configureGPU(bool _allowCPU);
 
 	bool init(
 		uint8_t const* _dag,
@@ -56,6 +56,9 @@ public:
 	void search_chunk(uint8_t const* header, uint64_t target, search_hook& hook);
 
 private:
+
+	static std::vector<cl::Device> getDevices(std::vector<cl::Platform> const& _platforms, unsigned _platformId);
+	
 	enum { c_max_search_results = 63, c_num_buffers = 2, c_hash_batch_size = 1024, c_search_batch_size = 1024*256 };
 
 	cl::Context m_context;
@@ -70,4 +73,5 @@ private:
 	unsigned m_workgroup_size;
 	bool m_opencl_1_1;
 
+	static bool s_allowCPU;
 };
diff --git a/libethash-cl/ethash_cl_miner_kernel.cl b/libethash-cl/ethash_cl_miner_kernel.cl
index 8567bb164..2143435ed 100644
--- a/libethash-cl/ethash_cl_miner_kernel.cl
+++ b/libethash-cl/ethash_cl_miner_kernel.cl
@@ -585,4 +585,4 @@ __kernel void ethash_search_chunks(
 		uint slot = min(convert_uint(MAX_OUTPUTS), convert_uint(atomic_inc(&g_output[0]) + 1));
 		g_output[slot] = gid;
 	}
-}
\ No newline at end of file
+}
diff --git a/libethcore/Ethash.cpp b/libethcore/Ethash.cpp
index 9ac4474ba..20ba539d1 100644
--- a/libethcore/Ethash.cpp
+++ b/libethcore/Ethash.cpp
@@ -381,9 +381,11 @@ void Ethash::GPUMiner::listDevices()
 	return ethash_cl_miner::listDevices();
 }
 
-bool Ethash::GPUMiner::configureGPU()
+bool Ethash::GPUMiner::configureGPU(unsigned _platformId, unsigned _deviceId, bool _allowCPU)
 {
-	return ethash_cl_miner::configureGPU();
+	s_platformId = _platformId;
+	s_deviceId = _deviceId;
+	return ethash_cl_miner::configureGPU(_allowCPU);
 }
 
 #endif
diff --git a/libethcore/Ethash.h b/libethcore/Ethash.h
index 49a8ae006..ee4c7d008 100644
--- a/libethcore/Ethash.h
+++ b/libethcore/Ethash.h
@@ -87,11 +87,8 @@ public:
 
 		static unsigned instances() { return s_numInstances > 0 ? s_numInstances : std::thread::hardware_concurrency(); }
 		static std::string platformInfo();
-		static void setDefaultPlatform(unsigned) {}
-		static void setDagChunks(unsigned) {}
-		static void setDefaultDevice(unsigned) {}
 		static void listDevices() {}
-		static bool configureGPU() { return false; }
+		static bool configureGPU(unsigned, unsigned, bool) { return false; }
 		static void setNumInstances(unsigned _instances) { s_numInstances = std::min<unsigned>(_instances, std::thread::hardware_concurrency()); }
 	protected:
 		void kickOff() override
@@ -120,9 +117,7 @@ public:
 		static std::string platformInfo();
 		static unsigned getNumDevices();
 		static void listDevices();
-		static bool configureGPU();
-		static void setDefaultPlatform(unsigned _id) { s_platformId = _id; }
-		static void setDefaultDevice(unsigned _id) { s_deviceId = _id; }
+		static bool configureGPU(unsigned _platformId, unsigned _deviceId, bool _allowCPU);
 		static void setNumInstances(unsigned _instances) { s_numInstances = std::min<unsigned>(_instances, getNumDevices()); }
 
 	protected: