diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index 88b85899d3095..7c1f9fad66746 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -1124,7 +1124,6 @@ The boot loader *must* fill out the following fields in bp,
 
     o hdr.code32_start
     o hdr.cmd_line_ptr
-    o hdr.cmdline_size
     o hdr.ramdisk_image (if applicable)
     o hdr.ramdisk_size  (if applicable)