diff --git a/services/spelling/install_deps.sh b/services/spelling/install_deps.sh
index edaa762ccf..b990b47423 100644
--- a/services/spelling/install_deps.sh
+++ b/services/spelling/install_deps.sh
@@ -1,9 +1,14 @@
+#!/bin/bash
+
+set -ex
+
 echo 'APT::Default-Release "stretch";' >/etc/apt/apt.conf.d/default-release
 
 # The following aspell packages exist in Ubuntu but not Debian:
 # aspell-af, aspell-id, aspell-nr, aspell-ns, aspell-ss, aspell-st, aspell-tn,
 # aspell-ts, aspell-xh, aspell-zu
-echo "deb http://archive.ubuntu.com/ubuntu/ bionic main universe" > /etc/apt/sources.list.d/bionic.list
+echo "deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ bionic main universe" > /etc/apt/sources.list.d/bionic-amd.list
+echo "deb [arch=arm64] http://ports.ubuntu.com/ubuntu-ports/ bionic main universe" > /etc/apt/sources.list.d/bionic-ports-arm.list
 apt-key adv --no-tty --keyserver keyserver.ubuntu.com --recv-keys 3B4FE6ACC0B21F32
 # Need to install aspell-or, aspell-ta and aspell-te from testing (buster) as
 # broken in stable (stretch).