diff --git a/bin/tests/system/isctest/kasp.py b/bin/tests/system/isctest/kasp.py
index 1aec27c3f5..501bd5f4a4 100644
--- a/bin/tests/system/isctest/kasp.py
+++ b/bin/tests/system/isctest/kasp.py
@@ -643,7 +643,9 @@ def check_keys(zone, keys, expected):
     def _verify_keys():
         # check number of keys matches expected.
         if len(keys) != len(expected):
-            return False
+            assert (
+                False
+            ), f"check_keys(): mismatched number of keys, expected {len(expected)}, got {len(keys)}"
 
         if len(keys) == 0:
             return True
@@ -662,7 +664,7 @@ def check_keys(zone, keys, expected):
                         expected[i].key = key
                 i += 1
             if not found:
-                return False
+                assert False, f"check_keys(): key {key} not found"
 
         return True
 
diff --git a/bin/tests/system/isctest/run.py b/bin/tests/system/isctest/run.py
index c3b37ac059..b26190e4a3 100644
--- a/bin/tests/system/isctest/run.py
+++ b/bin/tests/system/isctest/run.py
@@ -127,12 +127,22 @@ def perl(script: str, args: Optional[List[str]] = None) -> None:
 
 def retry_with_timeout(func, timeout, delay=1, msg=None):
     start_time = time.time()
+    exc_msg = None
     while time.time() < start_time + timeout:
-        if func():
-            return
+        exc_msg = None
+        try:
+            if func():
+                return
+        except AssertionError as exc:
+            exc_msg = str(exc)
         time.sleep(delay)
+    if exc_msg is not None:
+        isctest.log.error(exc_msg)
     if msg is None:
-        msg = f"{func.__module__}.{func.__qualname__} timed out after {timeout} s"
+        if exc_msg is not None:
+            msg = exc_msg
+        else:
+            msg = f"{func.__module__}.{func.__qualname__} timed out after {timeout} s"
     assert False, msg