diff --git a/src/leveled_sst.erl b/src/leveled_sst.erl
index e232372..d0ac95a 100644
--- a/src/leveled_sst.erl
+++ b/src/leveled_sst.erl
@@ -1519,11 +1519,11 @@ crc_check_slot(FullBin) ->
         PosBL:32/integer, 
         CRC32H:32/integer,
         Rest/binary>> = FullBin,
-    PosBL0 = min(PosBL, byte_size(FullBin) - 4), 
+    PosBL0 = min(PosBL, byte_size(FullBin) - 3), 
         % If the position has been bit-flipped to beyond the maximum paossible
         % length, use the maximum possible length
     <<Header:PosBL0/binary, Blocks/binary>> = Rest,
-    case {hmac(Header), hmac(PosBL)} of 
+    case {hmac(Header), hmac(PosBL0)} of 
         {CRC32H, CRC32PBL} ->
             {Header, Blocks};
         _ ->