diff --git a/doc/specs/vulkan/chapters/fxvertex.txt b/doc/specs/vulkan/chapters/fxvertex.txt
index 262e7605..8b8b599c 100644
--- a/doc/specs/vulkan/chapters/fxvertex.txt
+++ b/doc/specs/vulkan/chapters/fxvertex.txt
@@ -66,8 +66,8 @@ code:OpDecorate instruction.
                ...
                OpName %9 "variableName"
                OpName %15 "variableNameArray"
-               OpDecorate %18 Builtin VertexIndex
-               OpDecorate %19 Builtin InstanceIndex
+               OpDecorate %18 BuiltIn VertexIndex
+               OpDecorate %19 BuiltIn InstanceIndex
                OpDecorate %9 Location M
                OpDecorate %9 Component 2
                OpDecorate %15 Location N