diff -pruN 4.13.1-3/debian/changelog 4.13.1-3ubuntu1/debian/changelog
--- 4.13.1-3/debian/changelog	2022-01-19 10:14:42.000000000 +0000
+++ 4.13.1-3ubuntu1/debian/changelog	2022-01-24 10:07:32.000000000 +0000
@@ -1,3 +1,9 @@
+ocaml (4.13.1-3ubuntu1) jammy; urgency=medium
+
+  * Turn off LTO optimization, failing test: 'test.ml' with 2.1.1 (script).
+
+ -- Matthias Klose <doko@ubuntu.com>  Mon, 24 Jan 2022 11:07:32 +0100
+
 ocaml (4.13.1-3) unstable; urgency=medium
 
   * Upload to unstable
diff -pruN 4.13.1-3/debian/.gitattributes 4.13.1-3ubuntu1/debian/.gitattributes
--- 4.13.1-3/debian/.gitattributes	2022-01-19 10:14:42.000000000 +0000
+++ 4.13.1-3ubuntu1/debian/.gitattributes	1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-changelog merge=dpkg-mergechangelogs
diff -pruN 4.13.1-3/debian/rules 4.13.1-3ubuntu1/debian/rules
--- 4.13.1-3/debian/rules	2022-01-19 10:14:42.000000000 +0000
+++ 4.13.1-3ubuntu1/debian/rules	2022-01-24 10:07:32.000000000 +0000
@@ -50,7 +50,7 @@ export DH_OPTIONS
 export OCAML_OPT_ARCH
 export OCAML_STDLIB_DIR
 
-export DEB_BUILD_MAINT_OPTIONS=hardening=+bindnow
+export DEB_BUILD_MAINT_OPTIONS=hardening=+bindnow optimize=-lto
 export CCLINKFLAGS=$(shell dpkg-buildflags --get LDFLAGS)
 
 CONFIGURE_OPTS := \