diff --git a/docs/global_substitutions.txt b/docs/global_substitutions.txt
index 491b160..4dda1dc 100644
--- a/docs/global_substitutions.txt
+++ b/docs/global_substitutions.txt
@@ -6,11 +6,13 @@
 .. |COT| replace:: :term:`COT`
 .. |CSS| replace:: :term:`CSS`
 .. |CVE| replace:: :term:`CVE`
+.. |DTB| replace:: :term:`DTB`
 .. |DS-5| replace:: :term:`DS-5`
 .. |DSU| replace:: :term:`DSU`
 .. |DT| replace:: :term:`DT`
 .. |EL| replace:: :term:`EL`
 .. |EHF| replace:: :term:`EHF`
+.. |FCONF| replace:: :term:`FCONF`
 .. |FDT| replace:: :term:`FDT`
 .. |FIP| replace:: :term:`FIP`
 .. |FVP| replace:: :term:`FVP`