diff --git a/src/filo-fs-ext2.ads b/src/filo-fs-ext2.ads
index 5537507..bbf959b 100644
--- a/src/filo-fs-ext2.ads
+++ b/src/filo-fs-ext2.ads
@@ -98,7 +98,7 @@
 
    type Mount_State is record
       Part_Len             : Partition_Length := 0;
-      First_Data_Block     : FSBlock_Offset := 0;
+      First_Data_Block     : Unsigned_32 := Unsigned_32'First;
       Block_Size_Bits      : Log_Block_Size := Log_Block_Size'First;
       Block_Size           : Ext2.Block_Size := Ext2.Block_Size'First;
       Inodes_Per_Group     : Inode_Index := Inode_Index'First;