diff --git a/debian/changelog b/debian/changelog
index 048a672a0..84471f9c0 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -2,6 +2,7 @@ linux (4.19.28-2) UNRELEASED; urgency=medium
 
   * [x86,alpha,m68k] binfmt: Disable BINFMT_AOUT, IA32_AOUT, OSF4_COMPAT
   * [x86] Drop fix for #865303, which no longer affects Debian's OpenJDK
+  * udeb: Make serial_cs optional in serial-modules
 
  -- Ben Hutchings <ben@decadent.org.uk>  Tue, 12 Mar 2019 15:44:31 +0000
 
diff --git a/debian/installer/modules/serial-modules b/debian/installer/modules/serial-modules
index e046330c1..738348dd6 100644
--- a/debian/installer/modules/serial-modules
+++ b/debian/installer/modules/serial-modules
@@ -1,3 +1,3 @@
 rp2 ?
-serial_cs
+serial_cs ?
 synclink_cs ?