diff --git a/src/main.c b/src/main.c
index 4484f0a..e019765 100644
--- a/src/main.c
+++ b/src/main.c
@@ -69,7 +69,7 @@ static int trigger_event(block *const blocks, const unsigned short block_count,
 
 static int refresh_callback(block *const blocks,
                             const unsigned short block_count) {
-    if (execute_blocks(blocks, block_count, 0) != 0) {
+    if (execute_blocks(blocks, block_count, NULL) != 0) {
         return 1;
     }
 
diff --git a/src/timer.c b/src/timer.c
index 2454fb9..2ee555b 100644
--- a/src/timer.c
+++ b/src/timer.c
@@ -60,7 +60,7 @@ int timer_arm(timer *const timer) {
 }
 
 bool timer_must_run_block(const timer *const timer, const block *const block) {
-    if (timer->time == timer->reset_value) {
+    if (timer == NULL || timer->time == timer->reset_value) {
         return true;
     }