diff --git a/man/bootctl.xml b/man/bootctl.xml
index 5dfed110dd..5f5f137f8a 100644
--- a/man/bootctl.xml
+++ b/man/bootctl.xml
@@ -239,15 +239,25 @@
- Control creation and deletion of $ESP/$MACHINE_ID during
- and , respectively.
- auto is equivalent to to yes if /etc/machine-id
- resides on a filesystem other than tmpfs and no otherwise.
- Defaults to auto.
+ Control creation and deletion of the top-level machine ID directory on the file
+ system containing boot loader entries (i.e. beneath the file system returned by
+ --print-boot-path above) during and
+ , respectively. auto is equivalent to
+ yes if /etc/machine-id resides on a filesystem other than
+ tmpfs and no otherwise (in the latter case the machine ID is likely transient and
+ hence should not be used persistently in the ESP). Defaults to auto. See
+ machine-id5 for
+ details about the machine ID concept and file.
- Overriding this may be desired to hide the machine ID from the (unencrypted) ESP,
- configure a kernel-install8 script, or,
- conversely, commit a machine-id that only appears transient.
+ Overriding this may be desirable to hide the machine ID from the (unencrypted) ESP, configure a
+ kernel-install8
+ script, or, conversely, commit a transient machine ID.
+
+ The top-level machine ID directory is useful to allow smooth multi-boot installations: each
+ installed OS instance will have a different machine ID and thus a separate directory to place its
+ boot-time resources in. If this feature is turned off with this option, care needs to be taken that
+ multiple OS instances do not place conflicting files on the shared ESP and Extended Boot Loader
+ Partitions, or that multiple OS instances are not possible.