diff --git a/stratum/client.cpp b/stratum/client.cpp
index 0ce11cf..455ffbf 100644
--- a/stratum/client.cpp
+++ b/stratum/client.cpp
@@ -122,6 +122,7 @@ bool client_validate_user_address(YAAMP_CLIENT *client)
 			// debuglog("user %s testing on coin %s ...\n", client->username, coind->symbol);
 			if(!coind_can_mine(coind)) continue;
 			if(coind->pos) continue;
+			if(strlen(g_current_algo->name) && strcmp(g_current_algo->name, coind->algo)) continue;
 			if(coind_validate_user_address(coind, client->username)) {
 				debuglog("new user %s for coin %s\n", client->username, coind->symbol);
 				client->coinid = coind->id;
@@ -139,14 +140,25 @@ bool client_validate_user_address(YAAMP_CLIENT *client)
 	}
 
 	YAAMP_COIND *coind = (YAAMP_COIND *)object_find(&g_list_coind, client->coinid);
-	if(!coind) {
-		clientlog(client, "unable to find wallet for coinid %d...", client->coinid);
+	if (!coind) {
+		clientlog(client, "unable to find the wallet for coinid %d...", client->coinid);
 		return false;
+	} else {
+		if(g_current_algo && strlen(g_current_algo->name) && strcmp(g_current_algo->name, coind->algo)) {
+			clientlog(client, "%s address is on the wrong coin %s, reset to auto...", client->username, coind->symbol);
+			client->coinid = 0;
+			CommonLock(&g_db_mutex);
+			db_init_user_coinid(g_db, client);
+			CommonUnlock(&g_db_mutex);
+			return false;
+		}
 	}
 
 	bool isvalid = coind_validate_user_address(coind, client->username);
 	if (isvalid) {
 		client->coinid = coind->id;
+	} else {
+		clientlog(client, "unable to verify %s address for user coinid %d...", coind->symbol, client->coinid);
 	}
 	return isvalid;
 }
@@ -196,9 +208,8 @@ bool client_authorize(YAAMP_CLIENT *client, json_value *json_params)
 	debuglog("new client %s, %s, %s\n", client->username, client->password, client->version);
 #endif
 
-#ifdef NO_EXCHANGE
 	// when auto exchange is disabled, only authorize good wallet address...
-	if (!client_validate_user_address(client)) {
+	if (!g_autoexchange && !client_validate_user_address(client)) {
 
 		clientlog(client, "bad mining address %s", client->username);
 		client_send_result(client, "false");
@@ -209,7 +220,6 @@ bool client_authorize(YAAMP_CLIENT *client, json_value *json_params)
 
 		return false;
 	}
-#endif
 
 	client_send_result(client, "true");
 	client_send_difficulty(client, client->difficulty_actual);
diff --git a/stratum/client_submit.cpp b/stratum/client_submit.cpp
index 0860947..c59e150 100644
--- a/stratum/client_submit.cpp
+++ b/stratum/client_submit.cpp
@@ -63,6 +63,9 @@ void client_do_submit(YAAMP_CLIENT *client, YAAMP_JOB *job, YAAMP_JOB_VALUES *su
 		if(!templ->auxs[i]) continue;
 		YAAMP_COIND *coind_aux = templ->auxs[i]->coind;
 
+		if(!coind_aux || !strcmp(coind->symbol, coind_aux->symbol2))
+			continue;
+
 		unsigned char target_aux[1024];
 		binlify(target_aux, coind_aux->aux.target);
 
diff --git a/stratum/coind.h b/stratum/coind.h
index 9e3c6ef..c86d121 100644
--- a/stratum/coind.h
+++ b/stratum/coind.h
@@ -26,7 +26,9 @@ public:
 //	bool closing;
 
 	char name[1024];
-	char symbol[1024];
+	char symbol[256];
+	char symbol2[256];
+	char algo[256];
 	char wallet[1024];
 
 	char pubkey[1024];
diff --git a/stratum/coind_template.cpp b/stratum/coind_template.cpp
index 08c0126..a3a07e5 100644
--- a/stratum/coind_template.cpp
+++ b/stratum/coind_template.cpp
@@ -151,6 +151,16 @@ YAAMP_JOB_TEMPLATE *coind_create_template(YAAMP_COIND *coind)
 	if (strcmp(coind->symbol, "DRP")) // not in Dropcoin
 		strcpy(templ->flags, json_get_string(json_coinbaseaux, "flags"));
 
+	// temporary hack, until wallet is fixed...
+	if (!strcmp(coind->symbol, "MBL")) { // MBL: chainid in version
+		unsigned int nVersion = (unsigned int)json_get_int(json_result, "version");
+		if (nVersion & 0xFFFF0000UL == 0) {
+			nVersion |= (0x16UL << 16);
+			debuglog("%s version %s >> %08x\n", coind->symbol, templ->version, nVersion);
+		}
+		sprintf(templ->version, "%08x", nVersion);
+	}
+
 //	debuglog("%s ntime %s\n", coind->symbol, templ->ntime);
 //	uint64_t target = decode_compact(json_get_string(json_result, "bits"));
 //	coind->difficulty = target_to_diff(target);
diff --git a/stratum/db.cpp b/stratum/db.cpp
index e47ee31..4852ba2 100644
--- a/stratum/db.cpp
+++ b/stratum/db.cpp
@@ -141,7 +141,7 @@ void db_update_coinds(YAAMP_DB *db)
 
 	db_query(db, "select id, name, rpchost, rpcport, rpcuser, rpcpasswd, rpcencoding, master_wallet, reward, price, "\
 		"hassubmitblock, txmessage, enable, auto_ready, algo, pool_ttf, charity_address, charity_amount, charity_percent, "\
-		"reward_mul, symbol, auxpow, actual_ttf, network_ttf, usememorypool, hasmasternodes "\
+		"reward_mul, symbol, auxpow, actual_ttf, network_ttf, usememorypool, hasmasternodes, algo, symbol2 "\
 		"from coins where enable and auto_ready and algo='%s' order by index_avg", g_stratum_algo);
 
 	MYSQL_RES *result = mysql_store_result(&db->mysql);
@@ -207,6 +207,9 @@ void db_update_coinds(YAAMP_DB *db)
 		if(row[24]) coind->usememorypool = atoi(row[24]);
 		if(row[25]) coind->hasmasternodes = atoi(row[25]);
 
+		if(row[26]) strcpy(coind->algo, row[26]);
+		if(row[27]) strcpy(coind->symbol2, row[27]); // if pool + aux, prevent double submit
+
 		////////////////////////////////////////////////////////////////////////////////////////////////////
 
 		coind->touch = true;
diff --git a/stratum/job.cpp b/stratum/job.cpp
index 05b6e9b..0efddfa 100644
--- a/stratum/job.cpp
+++ b/stratum/job.cpp
@@ -18,13 +18,11 @@ static bool job_assign_client(YAAMP_JOB *job, YAAMP_CLIENT *client, double maxha
 	RETURN_ON_CONDITION(client_find_job_history(client, job->id), true);
 	RETURN_ON_CONDITION(maxhash > 0 && job->speed + client->speed > maxhash, true);
 
-#ifdef NO_EXCHANGE
-	if(maxhash >= 0. && client->coinid != job->coind->id) {
+	if(!g_autoexchange && maxhash >= 0. && client->coinid != job->coind->id) {
 		//debuglog("prevent client %c on %s, not the right coin\n",
 		//	client->username[0], job->coind->symbol);
-		return false;
+		return true;
 	}
-#endif
 
 	if(job->remote)
 	{
@@ -184,6 +182,7 @@ void job_assign_clients(YAAMP_JOB *job, double maxhash)
 
 void job_assign_clients_left(double factor)
 {
+	bool b;
 	for(CLI li = g_list_coind.first; li; li = li->next)
 	{
 		if(!job_has_free_client()) return;
@@ -198,13 +197,19 @@ void job_assign_clients_left(double factor)
 		for(CLI li = g_list_client.first; li; li = li->next)
 		{
 			YAAMP_CLIENT *client = (YAAMP_CLIENT *)li->data;
-#ifdef NO_EXCHANGE
-			debuglog("%s factor %f=>100 nethash %f\n", coind->symbol, factor, nethash);
-			if (client->coinid == coind->id)
-				factor = 100;
-#endif
-			bool b = job_assign_client(coind->job, client, nethash*factor);
-			if(!b) break;
+			if (!g_autoexchange) {
+				if (client->coinid == coind->id)
+					factor = 100.;
+				else
+					factor = 0.;
+			}
+
+			//debuglog("%s %s factor %f nethash %.3f\n", coind->symbol, client->username, factor, nethash);
+
+			if (factor > 0.) {
+				b = job_assign_client(coind->job, client, nethash*factor);
+				if(!b) break;
+			}
 		}
 
 		g_list_client.Leave();
diff --git a/stratum/stratum.cpp b/stratum/stratum.cpp
index e5a5ece..81f9657 100644
--- a/stratum/stratum.cpp
+++ b/stratum/stratum.cpp
@@ -30,6 +30,7 @@ double g_stratum_difficulty;
 int g_stratum_max_ttf;
 bool g_stratum_reconnect;
 bool g_stratum_renting;
+bool g_autoexchange = true;
 
 time_t g_last_broadcasted = 0;
 YAAMP_DB *g_db = NULL;
@@ -146,6 +147,11 @@ int main(int argc, char **argv)
 
 	initlog(argv[1]);
 
+#ifdef NO_EXCHANGE
+	// todo: init with a db setting or a yiimp shell command
+	g_autoexchange = false;
+#endif
+
 	char configfile[1024];
 	sprintf(configfile, "%s.conf", argv[1]);
 
diff --git a/stratum/stratum.h b/stratum/stratum.h
index 114d8e4..7203ef8 100644
--- a/stratum/stratum.h
+++ b/stratum/stratum.h
@@ -106,6 +106,8 @@ extern YAAMP_DB *g_db;
 extern YAAMP_ALGO g_algos[];
 extern YAAMP_ALGO *g_current_algo;
 
+extern bool g_autoexchange;
+
 /////////////////////////////////////////////////////////////////////////////////////////
 
 YAAMP_ALGO *stratum_find_algo(const char *name);
diff --git a/stratum/user.cpp b/stratum/user.cpp
index a58e611..e173ce6 100644
--- a/stratum/user.cpp
+++ b/stratum/user.cpp
@@ -122,7 +122,13 @@ void db_update_workers(YAAMP_DB *db)
 
 void db_init_user_coinid(YAAMP_DB *db, YAAMP_CLIENT *client)
 {
-	db_query(db, "UPDATE accounts SET coinid=%d WHERE id=%d AND IFNULL(coinid,0) = 0",
-		client->coinid, client->userid);
+	if (!client->userid)
+		return;
+
+	if (!client->coinid)
+		db_query(db, "UPDATE accounts SET coinid=NULL WHERE id=%d", client->userid);
+	else
+		db_query(db, "UPDATE accounts SET coinid=%d WHERE id=%d AND IFNULL(coinid,0) = 0",
+			client->coinid, client->userid);
 }