diff --git a/kernel/arch/armv8/syscall.c b/kernel/arch/armv8/syscall.c
index ad31f62..8219be1 100644
--- a/kernel/arch/armv8/syscall.c
+++ b/kernel/arch/armv8/syscall.c
@@ -92,7 +92,7 @@ handle_dispatcher_stop(
 {
     assert(argc == 2);
 
-    // TODO rueegges: kill using capability deletion once it is ready for last delete?
+    // NOTE rueegges: should kill using capability deletion but we did not implement that in the group projects
     scheduler_remove(to->u.dispatcher.dcb);
     wakeup_remove(to->u.dispatcher.dcb);
 
diff --git a/lib/aos/paging.c b/lib/aos/paging.c
index c9e4ec8..b9ce76d 100644
--- a/lib/aos/paging.c
+++ b/lib/aos/paging.c
@@ -563,7 +563,6 @@ errval_t paging_init_onthread(struct thread *t)
 
     debug_printf("paging_init_onthread thread id: %lx\n", t->id);
 
-    // TODO rueegges: Is this how we are supposed to get the exception handler stack?
     size_t stack_size = PT_STATIC_EXCEPTION_STACK_SIZE;
     struct capref frame;
     err = frame_alloc(&frame, stack_size, &stack_size);
@@ -979,6 +978,12 @@ static errval_t _paging_unmap(struct paging_state *st, const void *region)
         return LIB_ERR_PMAP_NOT_MAPPED;
     }
 
+    // we do not allow unmapping heap memory since malloc does
+    // not implement it anyways
+    if (vaddr_reg->heap) {
+        return LIB_ERR_PMAP_DO_SINGLE_UNMAP;
+    }
+
     struct pt_t *l0_pt = &st->l0_pt;
     assert(l0_pt->children != NULL);