diff --git a/libafl/src/events/llmp/restarting.rs b/libafl/src/events/llmp/restarting.rs
index 370b4ca39a..82630e0c0b 100644
--- a/libafl/src/events/llmp/restarting.rs
+++ b/libafl/src/events/llmp/restarting.rs
@@ -35,10 +35,10 @@ use serde::{Deserialize, Serialize};
 #[cfg(feature = "std")]
 use typed_builder::TypedBuilder;
 
-#[cfg(feature = "std")]
-use crate::events::{AdaptiveSerializer, CustomBufEventResult, HasCustomBufHandlers};
 #[cfg(all(unix, feature = "std", not(miri)))]
 use crate::events::EVENTMGR_SIGHANDLER_STATE;
+#[cfg(feature = "std")]
+use crate::events::{AdaptiveSerializer, CustomBufEventResult, HasCustomBufHandlers};
 use crate::{
     events::{
         Event, EventConfig, EventFirer, EventManager, EventManagerHooksTuple, EventManagerId,
diff --git a/libafl/src/stages/calibrate.rs b/libafl/src/stages/calibrate.rs
index c1c584af78..7a16cfa8ea 100644
--- a/libafl/src/stages/calibrate.rs
+++ b/libafl/src/stages/calibrate.rs
@@ -2,6 +2,7 @@
 
 use alloc::{
     borrow::{Cow, ToOwned},
+    string::ToString,
     vec::Vec,
 };
 use core::{fmt::Debug, marker::PhantomData, time::Duration};
@@ -260,7 +261,14 @@ where
             let map = observers[&self.map_observer_handle].as_ref();
 
             let mut bitmap_size = map.count_bytes();
-            assert!(bitmap_size != 0);
+
+            if bitmap_size < 1 {
+                return Err(Error::invalid_corpus(
+                    "This testcase doesnot trigger trigger any edges. Check your instrumentation!"
+                        .to_string(),
+                ));
+            }
+
             bitmap_size = bitmap_size.max(1); // just don't make it 0 because we take log2 of it later.
             let psmeta = state
                 .metadata_map_mut()