diff --git a/src/gruvin9x.cpp b/src/gruvin9x.cpp
index b6f8acef2..d1ca7bdd9 100644
--- a/src/gruvin9x.cpp
+++ b/src/gruvin9x.cpp
@@ -480,7 +480,11 @@ inline uint8_t keyDown()
 
 void clearKeyEvents()
 {
-    while(keyDown());  // loop until all keys are up
+#ifdef SIMU
+    while (keyDown() && main_thread_running);
+#else
+    while (keyDown());  // loop until all keys are up
+#endif
     putEvent(0);
 }
 
@@ -512,7 +516,9 @@ void doSplash()
       uint16_t tgtime = get_tmr10ms() + SPLASH_TIMEOUT;  //2sec splash screen
       while(tgtime != get_tmr10ms())
       {
-#ifndef SIMU
+#ifdef SIMU
+        if (!main_thread_running) return;
+#else
         getADC_filt();
 #endif
         uint16_t tsum = 0;
@@ -606,6 +612,10 @@ void checkSwitches()
   //loop until all switches are reset
   while (1)
   {
+#ifdef SIMU
+    if (!main_thread_running) return;
+#endif
+
     uint8_t i;
     for(i=SW_BASE; i<SW_Trainer; i++)
     {
@@ -645,6 +655,9 @@ void alert(const prog_char * s, bool defaults)
   clearKeyEvents();
   while(1)
   {
+#ifdef SIMU
+    if (!main_thread_running) return;
+#endif
     if(keyDown())   return;  //wait for key release
 
     if(getSwitch(g_eeGeneral.lightSw,0) || g_eeGeneral.lightAutoOff || defaults)
diff --git a/src/simpgmspace.cpp b/src/simpgmspace.cpp
index 18e28b125..09a5a505b 100644
--- a/src/simpgmspace.cpp
+++ b/src/simpgmspace.cpp
@@ -75,18 +75,21 @@ void *eeprom_write_function(void *)
   return 0;
 }
 
-bool main_thread_running = true;
+uint8_t main_thread_running = 0;
 void *main_thread(void *)
 {
   g_menuStack[0] = menuMainView;
   g_menuStack[1] = menuProcModelSelect;
 
   eeReadAll(); //load general setup and selected model
-  doSplash();
-  checkLowEEPROM();
-  checkTHR();
-  checkSwitches();
-  checkAlarm();
+
+  if (main_thread_running == 1) {
+    doSplash();
+    checkLowEEPROM();
+    checkTHR();
+    checkSwitches();
+    checkAlarm();
+  }
 
   while (main_thread_running) {
     perMain();
@@ -96,15 +99,15 @@ void *main_thread(void *)
 }
 
 pthread_t main_thread_pid;
-void StartMainThread()
+void StartMainThread(bool tests)
 {
-  main_thread_running = true;
+  main_thread_running = (tests ? 1 : 2);
   pthread_create(&main_thread_pid, NULL, &main_thread, NULL);
 }
 
 void StopMainThread()
 {
-  main_thread_running = false;
+  main_thread_running = 0;
   pthread_join(main_thread_pid, NULL);
 }
 
diff --git a/src/simpgmspace.h b/src/simpgmspace.h
index 21484382e..814226df5 100644
--- a/src/simpgmspace.h
+++ b/src/simpgmspace.h
@@ -89,6 +89,10 @@ extern sem_t eeprom_write_sem;
 #define RXCIE0 dummyport
 #define OCR0A dummyport
 
+#define OCR1B dummyport
+#define TCCR1A dummyport
+#define COM1B0 dummyport
+
 #define SPDR dummyport
 #define SPSR dummyport
 #define SPIF dummyport
@@ -126,8 +130,9 @@ extern sem_t eeprom_write_sem;
 
 extern volatile unsigned char pinb,pinc,pind,pine,ping,pinj,pinl;
 extern unsigned char portb,dummyport;
+extern uint8_t main_thread_running;
 
-void StartMainThread();
+void StartMainThread(bool tests=true);
 void StartEepromThread(const char *filename="eeprom.bin");
 
 extern const char *eepromFile;