Comment 2 for bug 1896608

Looking at the diff in http://launchpadlibrarian.net/497631450/grub2_2.04-1ubuntu26_2.04-1ubuntu26.4.diff.gz I see that this appears to be a new change during the SRU cycle, specifically:

"""
diff -Nru grub2-2.04/debian/grub-multi-install grub2-2.04/debian/grub-multi-install
--- grub2-2.04/debian/grub-multi-install 2020-04-15 11:31:27.000000000 +0000
+++ grub2-2.04/debian/grub-multi-install 2020-09-08 10:23:00.000000000 +0000
@@ -8,6 +8,13 @@

 . /usr/share/debconf/confmodule

+# shamelessly stolen from ucf:
+#
+# Load our templates, just in case our template has
+# not been loaded or the Debconf DB lost or corrupted
+# since then.
+db_x_loadtemplatefile "$(dpkg-query --control-path grub-common templates)" grub-common
+
 ###############################################################################
 # COPY FROM POSTINST
 ###############################################################################
@@ -373,7 +380,7 @@
         continue
       fi
     else
- break # noninteractive
+ exit 1 # noninteractive
     fi
   fi

@@ -395,7 +402,7 @@
         db_fset grub-efi/install_devices_empty seen false
       fi
     else
- break # noninteractive
+ exit 1 # noninteractive
     fi
   else
     break
"""

The new "exit 1" will break stable users that have answered the "grub-efi/install_devices_empty" question already with the answer "yes" because for those the question will be skipped (as it was already asked) and hence the if goes into the "exit 1" condition and the postinst fails.