diff --git a/apps/tests.h b/apps/tests.h
index 7e431b87..19cf416f 100644
--- a/apps/tests.h
+++ b/apps/tests.h
@@ -39,8 +39,8 @@
 //#define START_JOIN_TEST
 //#define START_PI
 //#define START_MEASURE_CTX_SWITCH
-//#define START_HELLO
-#define START_TESTS
+#define START_HELLO
+//#define START_TESTS
 //#define START_JACOBI
 
 // does our demos require GFX support?
diff --git a/arch/x86/kernel/gdt.c b/arch/x86/kernel/gdt.c
index c31797bb..8bb3b827 100644
--- a/arch/x86/kernel/gdt.c
+++ b/arch/x86/kernel/gdt.c
@@ -29,7 +29,7 @@
 
 gdt_ptr_t				gp;
 tss_t					task_state_segments[MAX_CORES] __attribute__ ((aligned (PAGE_SIZE)));
-static unsigned char			kstacks[MAX_TASKS][KERNEL_STACK_SIZE] __attribute__ ((aligned (PAGE_SIZE))) = {[0][0 ... KERNEL_STACK_SIZE-1] = 0xCD};
+static unsigned char			kstacks[MAX_TASKS][KERNEL_STACK_SIZE] __attribute__ ((aligned (PAGE_SIZE))) = {[0 ... MAX_TASKS-1][0 ... KERNEL_STACK_SIZE-1] = 0xCD};
 size_t					default_stack_pointer = (size_t) kstacks[0] + KERNEL_STACK_SIZE - 16; // => stack is 16byte aligned 
 // currently, our kernel has full access to the ioports
 static gdt_entry_t			gdt[GDT_ENTRIES] = {[0 ... GDT_ENTRIES-1] = {0, 0, 0, 0, 0, 0}};
diff --git a/include/metalsvm/tasks.h b/include/metalsvm/tasks.h
index 47c3c3f5..d1e70627 100644
--- a/include/metalsvm/tasks.h
+++ b/include/metalsvm/tasks.h
@@ -82,11 +82,15 @@ int create_kernel_task_on_core(tid_t* id, entry_point_t ep, void* arg, uint8_t p
  */
 static inline int create_kernel_task(tid_t* id, entry_point_t ep, void* arg, uint8_t prio)
 {
-	uint32_t core_id, flags;
+	uint32_t core_id;
 
-	flags = irq_nested_disable();
+#if MAX_CORES > 1
+	uint32_t flags = irq_nested_disable();
 	core_id = CORE_ID;
 	irq_nested_enable(flags);
+#else
+	core_id = 0;
+#endif
 
 	return create_kernel_task_on_core(id, ep, arg, prio, core_id);
 }
@@ -116,11 +120,15 @@ int create_user_task_on_core(tid_t* id, const char* fame, char** argv, uint32_t
  */
 static inline int create_user_task(tid_t* id, const char* fame, char** argv)
 {
-	uint32_t core_id, flags;
+	uint32_t core_id;
 
-	flags = irq_nested_disable();
+#if MAX_CORES > 1
+	uint32_t flags = irq_nested_disable();
 	core_id = CORE_ID;
 	irq_nested_enable(flags);
+#else
+	core_id = 0;
+#endif
 
 	return create_user_task_on_core(id, fame, argv, core_id);
 }