diff --git a/docs/COMMAND_LINE.MD b/docs/COMMAND_LINE.MD
index 5abf070..03a4248 100644
--- a/docs/COMMAND_LINE.MD
+++ b/docs/COMMAND_LINE.MD
@@ -29,6 +29,7 @@
 --no-upnp            Disable UPnP port forwarding
 --no-igd             An alias for --no-upnp
 --upnp-stratum       Port forward Stratum port (it's not forwarded by default)
+--merge-mine         IP:port and wallet address for another blockchain to merge mine with
 --version            Print p2pool's version and build details
 ```
 
@@ -50,3 +51,9 @@ In this example, you have local Monero host running on ports 18081/18083 (RPC/zm
 ```
 p2pool.exe --host 127.0.0.1 --host xmr1.rs.me --rpc-port 18089 --zmq-port 18084 --host xmr2.rs.me --host xmr3.rs.me --wallet YOUR_WALLET_ADDRESS
 ```
+
+### Merge mining
+
+```
+p2pool.exe --wallet YOUR_WALLET_ADDRESS --merge-mine IP:port YOUR_WALLET_ADDRESS_ON_ANOTHER_BLOCKCHAIN
+```
diff --git a/docs/MERGE_MINING.MD b/docs/MERGE_MINING.MD
index 223c721..a58f0c1 100644
--- a/docs/MERGE_MINING.MD
+++ b/docs/MERGE_MINING.MD
@@ -86,6 +86,8 @@ Example response 2: `{"jsonrpc":"2.0","id":"0","result":{}}`
 
 ### merge_mining_submit_solution
 
+Example request: `{"jsonrpc":"2.0","id":"0","method":"merge_mining_submit_solution","params":{"aux_blob":"4c6f72656d20697073756d","aux_hash":"f6952d6eef555ddd87aca66e56b91530222d6e318414816f3ba7cf5bf694bf0f","blob":"...","merkle_proof":["hash1","hash2","hash3"]}}`
+
 Request: a JSON containing these fields:
 Field|Description
 -|-
diff --git a/src/common.h b/src/common.h
index 7ab2c6f..db1c894 100644
--- a/src/common.h
+++ b/src/common.h
@@ -385,6 +385,8 @@ struct TxMempoolData
 
 struct AuxChainData
 {
+	FORCEINLINE AuxChainData(const hash& _id, const hash& _data, const difficulty_type& _difficulty) : unique_id(_id), data(_data), difficulty(_difficulty) {}
+
 	hash unique_id;
 	hash data;
 	difficulty_type difficulty;
diff --git a/src/keccak.h b/src/keccak.h
index 145df55..7274d61 100644
--- a/src/keccak.h
+++ b/src/keccak.h
@@ -42,18 +42,6 @@ FORCEINLINE void keccak(const uint8_t* in, int inlen, uint8_t (&md)[N])
 template<typename T>
 FORCEINLINE void keccak_custom(T&& in, int inlen, uint8_t* md, int mdlen)
 {
-	// TODO: remove after testing
-#if 0
-	if (inlen > 100) {
-		printf("\nkeccak_custom %d", inlen);
-		for (int i = 0; i < inlen; ++i) {
-			if ((i & 31) == 0) printf("\n");
-			printf("%02X ", static_cast<uint8_t>(in(i)));
-		}
-		printf("\n");
-	}
-#endif
-
 	uint64_t st[25] = {};
 
 	const int rsiz = sizeof(st) == mdlen ? KeccakParams::HASH_DATA_AREA : 200 - 2 * mdlen;
diff --git a/src/main.cpp b/src/main.cpp
index c1f9d12..3d3d2c4 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -62,6 +62,7 @@ void p2pool_usage()
 		"--no-igd             An alias for --no-upnp\n"
 		"--upnp-stratum       Port forward Stratum port (it's not forwarded by default)\n"
 #endif
+		"--merge-mine         IP:port and wallet address for another blockchain to merge mine with"
 		"--version            Print p2pool's version and build details\n"
 		"--help               Show this help message\n\n"
 		"Example command line:\n\n"
diff --git a/src/merge_mining_client.cpp b/src/merge_mining_client.cpp
index b078909..340d86a 100644
--- a/src/merge_mining_client.cpp
+++ b/src/merge_mining_client.cpp
@@ -27,10 +27,10 @@ LOG_CATEGORY(MergeMiningClient)
 
 namespace p2pool {
 
-MergeMiningClient::MergeMiningClient(p2pool* pool, const std::string& host, const std::string& address)
+MergeMiningClient::MergeMiningClient(p2pool* pool, const std::string& host, const std::string& wallet)
 	: m_host(host)
 	, m_port(80)
-	, m_auxAddress(address)
+	, m_auxWallet(wallet)
 	, m_ping(0.0)
 	, m_pool(pool)
 	, m_loop{}
@@ -42,7 +42,7 @@ MergeMiningClient::MergeMiningClient(p2pool* pool, const std::string& host, cons
 	const size_t k = host.find_last_of(':');
 	if (k != std::string::npos) {
 		m_host = host.substr(0, k);
-		m_port = strtoul(host.substr(k + 1).c_str(), nullptr, 10);
+		m_port = std::stoul(host.substr(k + 1), nullptr, 10);
 	}
 
 	if (m_host.empty() || (m_port == 0) || (m_port >= 65536)) {
@@ -95,7 +95,7 @@ MergeMiningClient::~MergeMiningClient()
 void MergeMiningClient::on_timer()
 {
 	MinerData data = m_pool->miner_data();
-	merge_mining_get_job(data.height, data.prev_id, m_auxAddress, m_auxHash);
+	merge_mining_get_job(data.height, data.prev_id, m_auxWallet, m_auxHash);
 }
 
 void MergeMiningClient::merge_mining_get_chain_id()
@@ -157,7 +157,7 @@ bool MergeMiningClient::parse_merge_mining_get_chain_id(const char* data, size_t
 	return true;
 }
 
-void MergeMiningClient::merge_mining_get_job(uint64_t height, const hash& prev_id, const std::string& address, const hash& aux_hash)
+void MergeMiningClient::merge_mining_get_job(uint64_t height, const hash& prev_id, const std::string& wallet, const hash& aux_hash)
 {
 	if (m_getJobRunning) {
 		return;
@@ -169,7 +169,7 @@ void MergeMiningClient::merge_mining_get_job(uint64_t height, const hash& prev_i
 	log::Stream s(buf);
 
 	s << "{\"jsonrpc\":\"2.0\",\"id\":\"0\",\"method\":\"merge_mining_get_job\",\"params\":{"
-	  << "\"address\":\"" << address << '"'
+	  << "\"address\":\"" << wallet << '"'
 	  << ",\"aux_hash\":\"" << aux_hash << '"'
 	  << ",\"height\":" << height
 	  << ",\"prev_id\":\"" << prev_id << '"'
diff --git a/src/merge_mining_client.h b/src/merge_mining_client.h
index 54ca44f..14f2f17 100644
--- a/src/merge_mining_client.h
+++ b/src/merge_mining_client.h
@@ -26,11 +26,15 @@ class p2pool;
 class MergeMiningClient
 {
 public:
-	MergeMiningClient(p2pool* pool, const std::string& host, const std::string& address);
+	MergeMiningClient(p2pool* pool, const std::string& host, const std::string& wallet);
 	~MergeMiningClient();
 
 	void merge_mining_submit_solution(const std::vector<uint8_t>& blob, const std::vector<hash>& merkle_proof);
 
+	FORCEINLINE const hash& aux_id() const { return m_chainID; }
+	FORCEINLINE const hash& aux_data() const { return m_auxHash; }
+	FORCEINLINE const difficulty_type& aux_diff() const { return m_auxDiff; }
+
 private:
 	static void loop(void* data);
 
@@ -40,7 +44,7 @@ private:
 	void merge_mining_get_chain_id();
 	bool parse_merge_mining_get_chain_id(const char* data, size_t size);
 
-	void merge_mining_get_job(uint64_t height, const hash& prev_id, const std::string& address, const hash& aux_hash);
+	void merge_mining_get_job(uint64_t height, const hash& prev_id, const std::string& wallet, const hash& aux_hash);
 	bool parse_merge_mining_get_job(const char* data, size_t size);
 
 	bool parse_merge_mining_submit_solution(const char* data, size_t size);
@@ -48,7 +52,7 @@ private:
 	std::string m_host;
 	uint32_t m_port;
 
-	std::string m_auxAddress;
+	std::string m_auxWallet;
 	std::vector<uint8_t> m_auxBlob;
 	hash m_auxHash;
 	difficulty_type m_auxDiff;
diff --git a/src/p2pool.cpp b/src/p2pool.cpp
index cb52eae..5b88d74 100644
--- a/src/p2pool.cpp
+++ b/src/p2pool.cpp
@@ -37,6 +37,7 @@
 #include "pool_block.h"
 #include "keccak.h"
 #include "merkle.h"
+#include "merge_mining_client.h"
 #include <thread>
 #include <fstream>
 #include <numeric>
@@ -186,6 +187,11 @@ p2pool::~p2pool()
 	}
 #endif
 
+	for (const MergeMiningClient* c : m_mergeMiningClients) {
+		delete c;
+	}
+	m_mergeMiningClients.clear();
+
 	uv_rwlock_destroy(&m_mainchainLock);
 	uv_rwlock_destroy(&m_minerDataLock);
 	uv_rwlock_destroy(&m_ZMQReaderLock);
@@ -334,6 +340,25 @@ void p2pool::handle_miner_data(MinerData& data)
 		cleanup_mainchain_data(data.height);
 	}
 
+	data.aux_chains.clear();
+
+	if (!m_mergeMiningClients.empty()) {
+		data.aux_chains.reserve(m_mergeMiningClients.size());
+
+		std::vector<hash> tmp;
+		tmp.reserve(m_mergeMiningClients.size());
+
+		for (const MergeMiningClient* c : m_mergeMiningClients) {
+			data.aux_chains.emplace_back(c->aux_id(), c->aux_data(), c->aux_diff());
+			tmp.emplace_back(c->aux_data());
+		}
+
+		if (!find_aux_nonce(tmp, data.aux_nonce)) {
+			LOGERR(1, "Failed to find the aux nonce for merge mining. Merge mining will be off this round.");
+			data.aux_chains.clear();
+		}
+	}
+
 	// TODO: remove after testing
 #if 0
 	{
@@ -840,6 +865,10 @@ void p2pool::download_block_headers(uint64_t current_height)
 						}
 					}
 
+					for (const auto& h : m_params->m_mergeMiningHosts) {
+						m_mergeMiningClients.push_back(new MergeMiningClient(this, h.m_host, h.m_wallet));
+					}
+
 					m_startupFinished = true;
 				}
 			}
@@ -1136,11 +1165,10 @@ void p2pool::get_miner_data(bool retry)
 					std::this_thread::sleep_for(std::chrono::milliseconds(1000));
 					m_getMinerDataPending = false;
 					get_miner_data();
+					return;
 				}
 			}
-			else {
-				m_getMinerDataPending = false;
-			}
+			m_getMinerDataPending = false;
 		});
 }
 
diff --git a/src/p2pool.h b/src/p2pool.h
index 9f16512..3cccabd 100644
--- a/src/p2pool.h
+++ b/src/p2pool.h
@@ -33,6 +33,7 @@ class Miner;
 class ConsoleCommands;
 class p2pool_api;
 class ZMQReader;
+class MergeMiningClient;
 struct PoolBlock;
 
 class p2pool : public MinerCallbackHandler, public nocopy_nomove
@@ -226,6 +227,8 @@ private:
 	mutable uv_rwlock_t m_ZMQReaderLock;
 	ZMQReader* m_ZMQReader = nullptr;
 
+	std::vector<MergeMiningClient*> m_mergeMiningClients;
+
 	hash m_getMinerDataHash;
 	bool m_getMinerDataPending = false;
 
diff --git a/src/params.cpp b/src/params.cpp
index de5ed45..e0d508e 100644
--- a/src/params.cpp
+++ b/src/params.cpp
@@ -189,6 +189,12 @@ Params::Params(int argc, char* const argv[])
 		}
 #endif
 
+		if ((strcmp(argv[i], "--merge-mine") == 0) && (i + 2 < argc)) {
+			m_mergeMiningHosts.emplace_back(argv[i + 1], argv[i + 2]);
+			i += 2;
+			ok = true;
+		}
+
 		if (!ok) {
 			fprintf(stderr, "Unknown command line parameter %s\n\n", argv[i]);
 			p2pool_usage();
diff --git a/src/params.h b/src/params.h
index a23e7aa..0458434 100644
--- a/src/params.h
+++ b/src/params.h
@@ -53,6 +53,16 @@ struct Params
 
 	std::vector<Host> m_hosts;
 
+	struct MergeMiningHost
+	{
+		MergeMiningHost(const char* host, const char* wallet) : m_host(host), m_wallet(wallet) {}
+
+		std::string m_host;
+		std::string m_wallet;
+	};
+
+	std::vector<MergeMiningHost> m_mergeMiningHosts;
+
 	bool m_lightMode = false;
 	Wallet m_wallet{ nullptr };
 	std::string m_stratumAddresses;
diff --git a/src/tcp_server.cpp b/src/tcp_server.cpp
index e276a74..f11b76f 100644
--- a/src/tcp_server.cpp
+++ b/src/tcp_server.cpp
@@ -113,7 +113,7 @@ void TCPServer::parse_address_list_internal(const std::string& address_list, Cal
 				}
 			}
 
-			const int port = strtol(address.substr(k2 + 1).c_str(), nullptr, 10);
+			const uint32_t port = std::stoul(address.substr(k2 + 1), nullptr, 10);
 			if ((port > 0) && (port < 65536)) {
 				callback(is_v6, address, ip, port);
 			}
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 173369f..00f640d 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -53,6 +53,7 @@ set(SOURCES
 	../src/log.cpp
 	../src/memory_leak_debug.cpp
 	../src/mempool.cpp
+	../src/merge_mining_client.cpp
 	../src/merkle.cpp
 	../src/miner.cpp
 	../src/p2p_server.cpp