diff --git a/docker/common.sh b/docker/common.sh
index 3b6beb966..493957199 100755
--- a/docker/common.sh
+++ b/docker/common.sh
@@ -3,6 +3,12 @@
 set -x
 set -euo pipefail
 
+# For architectures except amd64 and i386, look for packages on ports.ubuntu.com instead.
+# This is important if you enable additional architectures so you can install libraries to cross-compile against.
+# Look for 'dpkg --add-architecture' in the README for more details.
+sed 's/http:\/\/\(.*\).ubuntu.com\/ubuntu\//[arch-=amd64,i386] http:\/\/ports.ubuntu.com\/ubuntu-ports\//g' /etc/apt/sources.list > /etc/apt/sources.list.d/ports.list
+sed -i 's/http:\/\/\(.*\).ubuntu.com\/ubuntu\//[arch=amd64,i386] http:\/\/\1.archive.ubuntu.com\/ubuntu\//g' /etc/apt/sources.list
+
 apt-get update
 
 apt-get install -y --no-install-recommends \