diff --git a/kernel/tasks.c b/kernel/tasks.c
index 48182a9b..bf57dda0 100644
--- a/kernel/tasks.c
+++ b/kernel/tasks.c
@@ -52,7 +52,9 @@ static task_t task_table[MAX_TASKS] = { \
 static spinlock_irqsave_t table_lock = SPINLOCK_IRQSAVE_INIT;
 
 DEFINE_PER_CORE(task_t*, current_task, task_table+0);
+#if MAX_CORES > 1
 DEFINE_PER_CORE_STATIC(task_t*, old_task, NULL);
+#endif
 
 /** @brief helper function for the assembly code to determine the current task
  * @return Pointer to the task_t structure of current task
@@ -177,6 +179,7 @@ void NORETURN abort(void) {
  */
 inline static void task_switch_finished(void)
 {
+#if MAX_CORES > 1
 	uint32_t flags = irq_nested_disable();
 
 	// do we already reset the TASK_SWITCH_IN_PROGRESS bit?
@@ -187,6 +190,7 @@ inline static void task_switch_finished(void)
 	}
 
 	irq_nested_enable(flags);
+#endif
 }
 
 /** @brief Create a task with a specific entry point
@@ -839,10 +843,14 @@ void scheduler(void)
 		if ((task_table[new_id].status == TASK_READY) && !(task_table[new_id].flags & TASK_SWITCH_IN_PROGESS)) {
 			if (curr_task->status == TASK_RUNNING) {
 				curr_task->status = TASK_READY;
+#if MAX_CORES > 1
 				curr_task->flags |= TASK_SWITCH_IN_PROGESS;
 				per_core(old_task) = curr_task;
-			} else per_core(old_task) = NULL;
-
+#endif
+			}
+#if MAX_CORES > 1
+				else per_core(old_task) = NULL;
+#endif
 			task_table[new_id].status = TASK_RUNNING;
 			curr_task = per_core(current_task) = task_table+new_id;
 
@@ -853,8 +861,10 @@ void scheduler(void)
 		//	kprintf("task switch %d is in progress\n", new_id);
 	}
 
+#if MAX_CORES > 1
 	// old task will never rescheduled
 	per_core(old_task) = NULL;
+#endif
 
 	if ((curr_task->status == TASK_RUNNING) || (curr_task->status == TASK_IDLE))
 		goto get_task_out;