diff --git a/src/environment.c b/src/environment.c
index 081ae3c1..790ec63f 100644
--- a/src/environment.c
+++ b/src/environment.c
@@ -14,6 +14,7 @@ void Environment_start(Environment *self) {
 }
 
 int Environment_wait_until(Environment *self, instant_t wakeup_time) {
+  puts("wait until env");
   hardware_wait_for(self->current_tag.time, wakeup_time);
   return 0;
 }
@@ -28,5 +29,7 @@ void Environment_ctor(Environment *self, Reactor *main) {
   self->running = false;
   self->wait_until = Environment_wait_until;
   self->calculate_levels = Environment_calculate_levels;
+  self->current_tag.time = 0;
+  self->current_tag.microstep = 0;
   Scheduler_ctor(&self->scheduler, self);
 }
diff --git a/src/hardware/riot/riot_implementation.c b/src/hardware/riot/riot_implementation.c
index 8861744c..6b42ff65 100644
--- a/src/hardware/riot/riot_implementation.c
+++ b/src/hardware/riot/riot_implementation.c
@@ -12,13 +12,14 @@ void hardware_wait_for(instant_t current_time, instant_t wake_up_time) {
   //ztimer_t timeout = { .callback=callback, .arg="Hello ztimer!" };
   //ztimer_set(ZTIMER_SEC, &timeout, 2);
 
+  puts("riot sleep");
   if (IS_USED(MODULE_ZTIMER)) {
+    puts("calculating delta");
     int64_t time_delta = wake_up_time - current_time;
     int64_t usec = time_delta / 1000;
-
-    printf("sleeping microseconds %lli\n", usec);
     ztimer_sleep(ZTIMER_USEC, usec);
   } else {
+    puts("boring sleep");
     uint32_t loops = coreclk() / 20;
     for (volatile uint32_t i = 0; i < loops; i++) { }
   }
diff --git a/src/scheduler.c b/src/scheduler.c
index 199b9358..d41370f2 100644
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -23,17 +23,33 @@ void Scheduler_prepare_timestep(Scheduler *self) {
 void Scheduler_run(Scheduler *self) {
   puts("entering main-loop");
 
-  while(true) {}
-
   while (!self->event_queue_.empty(&self->event_queue_)) {
     // fetch tag from next event in queue
+    puts("fetching next tag");
     tag_t next_tag = self->event_queue_.next_tag(&self->event_queue_);
 
+    puts("waituntil");
+
+    if (self == NULL) {
+      puts("self is NULL");
+    }
+
+    if (self->env_ == NULL) {
+      puts("env is NULL");
+    }
+
+    if (self->env_->wait_until == NULL) {
+      puts("wait_until is NULL");
+    }
+
     // sleep until this time
-    puts("waiting until");
+    while (true) {}
     self->env_->wait_until(self->env_, next_tag.time);
+    puts("done waiting");
+    //while(true) {}
 
     puts("processing tag");
+
     // process this tag
     do {
       self->prepare_time_step(self);
@@ -58,7 +74,6 @@ void Scheduler_run(Scheduler *self) {
       reaction->body(reaction);
     }
   }
-  printf("Scheduler out of events. Shutting down.\n");
 }
 
 void Scheduler_recursive_level(Reactor *reactor, int current_level) {