diff --git a/shared/src/main/scala/io/kaitai/struct/format/AttrSpec.scala b/shared/src/main/scala/io/kaitai/struct/format/AttrSpec.scala
index 09e1b941f..fcccc12fc 100644
--- a/shared/src/main/scala/io/kaitai/struct/format/AttrSpec.scala
+++ b/shared/src/main/scala/io/kaitai/struct/format/AttrSpec.scala
@@ -179,11 +179,11 @@ object AttrSpec {
     val sizeEos = ParseUtils.getOptValueBool(srcMap, "size-eos", path).getOrElse(false)
     val ifExpr = ParseUtils.getOptValueExpression(srcMap, "if", path)
     val encoding = ParseUtils.getOptValueStr(srcMap, "encoding", path)
-    val terminator = ParseUtils.getOptValueInt(srcMap, "terminator", path)
+    val terminator = ParseUtils.getOptValueByte(srcMap, "terminator", path)
     val consume = ParseUtils.getOptValueBool(srcMap, "consume", path).getOrElse(true)
     val include = ParseUtils.getOptValueBool(srcMap, "include", path).getOrElse(false)
     val eosError = ParseUtils.getOptValueBool(srcMap, "eos-error", path).getOrElse(true)
-    val padRight = ParseUtils.getOptValueInt(srcMap, "pad-right", path)
+    val padRight = ParseUtils.getOptValueByte(srcMap, "pad-right", path)
     val enumOpt = ParseUtils.getOptValueStr(srcMap, "enum", path)
     val parent = ParseUtils.getOptValueExpression(srcMap, "parent", path)
     val valid = srcMap.get("valid").map(ValidationSpec.fromYaml(_, path ++ List("valid")))
diff --git a/shared/src/main/scala/io/kaitai/struct/format/ParseUtils.scala b/shared/src/main/scala/io/kaitai/struct/format/ParseUtils.scala
index 97652f03d..1481cddcb 100644
--- a/shared/src/main/scala/io/kaitai/struct/format/ParseUtils.scala
+++ b/shared/src/main/scala/io/kaitai/struct/format/ParseUtils.scala
@@ -72,6 +72,15 @@ object ParseUtils {
     }
   }
 
+  def getOptValueByte(src: Map[String, Any], field: String, path: List[String]): Option[Int] = {
+    getOptValueInt(src, field, path).map { value =>
+      if (value < 0 || value > 255) {
+        throw KSYParseError.withText(s"expected an integer from 0 to 255, got ${value}", path ++ List(field))
+      }
+      value
+    }
+  }
+
   def getValueIdentifier(src: Map[String, Any], idx: Int, entityName: String, path: List[String]): Identifier = {
     getOptValueStr(src, "id", path) match {
       case Some(idStr) =>