diff --git a/storage/tests/python/src/consts.py b/storage/tests/python/src/consts.py
index a02d6a72fa..39e0a186d2 100644
--- a/storage/tests/python/src/consts.py
+++ b/storage/tests/python/src/consts.py
@@ -70,7 +70,6 @@ WIPE_CODE_TAG_SIZE = 8
 WIPE_CODE_EMPTY = "\0\0\0\0"
 
 # Size of counter. 4B integer and 8B tail.
-COUNTER_TAIL = 12
 COUNTER_TAIL_SIZE = 8
 COUNTER_MAX_TAIL = 64
 
diff --git a/storage/tests/python/src/norcow.py b/storage/tests/python/src/norcow.py
index f3c9510d57..f7cbb4ad4d 100644
--- a/storage/tests/python/src/norcow.py
+++ b/storage/tests/python/src/norcow.py
@@ -22,11 +22,21 @@ class Norcow:
             for sector in range(consts.NORCOW_SECTOR_COUNT):
                 if self.sectors[sector][:8] == consts.NORCOW_MAGIC_AND_VERSION:
                     self.active_sector = sector
-                    self.active_offset = len(consts.NORCOW_MAGIC_AND_VERSION)
+                    self.active_offset = self.find_free_offset()
                     break
         else:
             self.wipe()
 
+    def find_free_offset(self):
+        offset = len(consts.NORCOW_MAGIC_AND_VERSION)
+        while True:
+            try:
+                k, v = self._read_item(offset)
+            except ValueError:
+                break
+            offset = offset + self._norcow_item_length(v)
+        return offset
+
     def wipe(self, sector: int = None):
         if sector is None:
             sector = self.active_sector
diff --git a/storage/tests/tests/test_set_get.py b/storage/tests/tests/test_set_get.py
index 5fce933641..b2a03b0eb9 100644
--- a/storage/tests/tests/test_set_get.py
+++ b/storage/tests/tests/test_set_get.py
@@ -165,8 +165,8 @@ def test_set_locked():
     assert common.memory_equals(sc, sp)
 
     for s in (sc, sp):
-        s.get(0xC001) == b"Ahoj"
-        s.get(0xC003) == b"test"
+        assert s.get(0xC001) == b"Ahoj"
+        assert s.get(0xC003) == b"test"
 
 
 def test_counter():