diff --git a/man/ostree-prepare-root.xml b/man/ostree-prepare-root.xml
index 70371b7bc5..ae269ef430 100644
--- a/man/ostree-prepare-root.xml
+++ b/man/ostree-prepare-root.xml
@@ -130,7 +130,8 @@ License along with this library. If not, see .
directory is *not* a symlink to /var/opt, but is just an empty directory.
- Note the /usr mount point remains read-only by default. This option is independent of etc.transient and sysroot.readonly;
+ If this option is not combined with composefs.enabled, then /usr mount point remains read-only by default.
+ This option is independent of etc.transient and sysroot.readonly;
it is supported for example to have root.transient=true but etc.transient=false in which case changes to /etc continue
to persist across updates, with the default OSTree 3-way merge applied.