diff --git a/docs/spec/blocks/index.adoc b/docs/spec/blocks/index.adoc
index 6bbb6e8..9ec742d 100644
--- a/docs/spec/blocks/index.adoc
+++ b/docs/spec/blocks/index.adoc
@@ -56,7 +56,7 @@ typedef struct IndexEntry
     /**Type of item pointed by this entry */
     uint32_t blockType;
     /**Type of data contained by the block pointed by this entry */
-    uint32_t dataType;
+    uint16_t dataType;
     /**Offset in file where item is stored */
     uint64_t offset;
 } IndexEntry;
@@ -75,8 +75,8 @@ typedef struct IndexEntry
 |blockType
 |The type of block this entry points to.
 
-|uint32_t
-|4 bytes
+|uint16_t
+|2 bytes
 |dataType
 |The type of data the block pointed by this entry contains.
 
diff --git a/docs/spec/blocks/index2.adoc b/docs/spec/blocks/index2.adoc
index 62135a4..72a64eb 100644
--- a/docs/spec/blocks/index2.adoc
+++ b/docs/spec/blocks/index2.adoc
@@ -54,7 +54,7 @@ typedef struct IndexEntry
     /**Type of item pointed by this entry */
     uint32_t blockType;
     /**Type of data contained by the block pointed by this entry */
-    uint32_t dataType;
+    uint16_t dataType;
     /**Offset in file where item is stored */
     uint64_t offset;
 } IndexEntry;
@@ -74,7 +74,7 @@ typedef struct IndexEntry
 |The type of block this entry points to.
 
 |uint32_t
-|4 bytes
+|2 bytes
 |dataType
 |The type of data the block pointed by this entry contains.
 
diff --git a/include/aaruformat/structs.h b/include/aaruformat/structs.h
index a18ec50..fa80fac 100644
--- a/include/aaruformat/structs.h
+++ b/include/aaruformat/structs.h
@@ -138,7 +138,7 @@ typedef struct IndexEntry
     /**Type of item pointed by this entry */
     uint32_t blockType;
     /**Type of data contained by the block pointed by this entry */
-    uint32_t dataType;
+    uint16_t dataType;
     /**Offset in file where item is stored */
     uint64_t offset;
 } IndexEntry;