diff --git a/MiSTer.ini b/MiSTer.ini
index 019d0df..cbe33d0 100644
--- a/MiSTer.ini
+++ b/MiSTer.ini
@@ -361,3 +361,6 @@ controller_unique_mapping=0
 ; code if less than osd_lock_time seconds have passed since the OSD was closed.
 ; set to 0 for manual lock from OSD
 osd_lock_time=5
+
+; use custom main for specific core. This option should be used only inside specific core.
+;main=some_binary_file
diff --git a/cfg.cpp b/cfg.cpp
index 34c4aac..118637d 100644
--- a/cfg.cpp
+++ b/cfg.cpp
@@ -130,6 +130,7 @@ static const ini_var_t ini_vars[] =
 	{ "OSD_LOCK", (void*)(&(cfg.osd_lock)), STRING, 0, sizeof(cfg.osd_lock) - 1 },
 	{ "OSD_LOCK_TIME", (void*)(&(cfg.osd_lock_time)), UINT16, 0, 60 },
 	{ "DEBUG", (void *)(&(cfg.debug)), UINT8, 0, 1 },
+	{ "MAIN", (void*)(&(cfg.main)), STRING, 0, sizeof(cfg.main) - 1 },
 };
 
 static const int nvars = (int)(sizeof(ini_vars) / sizeof(ini_var_t));
@@ -555,6 +556,7 @@ void cfg_parse()
 	cfg.video_saturation = 100;
 	cfg.video_hue = 0;
 	strcpy(cfg.video_gain_offset, "1, 0, 1, 0, 1, 0");
+	strcpy(cfg.main, "MiSTer");
 	has_video_sections = false;
 	using_video_section = false;
 	cfg_error_count = 0;
diff --git a/cfg.h b/cfg.h
index b7b9656..491ba29 100644
--- a/cfg.h
+++ b/cfg.h
@@ -98,6 +98,7 @@ typedef struct {
 	char osd_lock[25];
 	uint16_t osd_lock_time;
 	char debug;
+	char main[1024];
 } cfg_t;
 
 extern cfg_t cfg;
diff --git a/fpga_io.cpp b/fpga_io.cpp
index 51c4811..a313a76 100644
--- a/fpga_io.cpp
+++ b/fpga_io.cpp
@@ -610,7 +610,7 @@ char *getappname()
 	return dest;
 }
 
-void app_restart(const char *path, const char *xml)
+void app_restart(const char *path, const char *xml, const char *exe)
 {
 	sync();
 	fpga_core_reset(1);
@@ -620,8 +620,8 @@ void app_restart(const char *path, const char *xml)
 
 	offload_stop();
 
-	char *appname = getappname();
-	printf("restarting the %s\n", appname);
+	const char *appname = exe ? exe : getappname();
+	printf("restarting to %s\n", appname);
 	execl(appname, appname, path, xml, NULL);
 
 	printf("Something went wrong. Rebooting...\n");
diff --git a/fpga_io.h b/fpga_io.h
index 5448e24..cba66c3 100644
--- a/fpga_io.h
+++ b/fpga_io.h
@@ -36,7 +36,7 @@ int fpga_get_io_version();
 int fpga_load_rbf(const char *name, const char *cfg = 0, const char *xml = 0);
 
 void reboot(int cold);
-void app_restart(const char *path, const char *xml = 0);
+void app_restart(const char *path, const char *xml = 0, const char *exe = 0);
 char *getappname();
 
 void fpga_wait_to_reset();
diff --git a/user_io.cpp b/user_io.cpp
index c51a17b..44e62c7 100644
--- a/user_io.cpp
+++ b/user_io.cpp
@@ -1376,6 +1376,13 @@ void user_io_init(const char *path, const char *xml)
 		sleep(1);
 	}
 
+	const char *main = getFullPath(cfg.main);
+	if (strcasecmp(main, getappname()) && FileExists(main))
+	{
+		printf("Current exec is %s, core requires exec %s\n", getappname(), main);
+		app_restart(path, xml, main);
+	}
+
 	uint8_t hotswap[4] = {};
 	ide_reset(hotswap);
 
@@ -3119,7 +3126,7 @@ void user_io_poll()
 			else if (op & 1)
 			{
 				uint32_t buf_n = sizeof(buffer[0]) / blksz;
-				int psx_blksz = 0;
+				unsigned int psx_blksz = 0;
 				if (is_psx() && blksz == 2352)
 				{
 					//returns 0 if the mounted disk is not a chd, otherwise returns the chd hunksize in bytes