diff --git a/.ci/build.sh b/.ci/build.sh
index 28db0441a..e26bbe8bf 100755
--- a/.ci/build.sh
+++ b/.ci/build.sh
@@ -603,7 +603,7 @@ else
         grep -q " bullseye " /etc/apt/sources.list || echo [!] WARNING: System not running the expected Debian version
 
 	# Establish general dependencies.
-	pkgs="cmake ninja-build pkg-config git wget p7zip-full extra-cmake-modules wayland-protocols tar gzip file appstream qttranslations5-l10n python3-pip python3-venv"
+	pkgs="cmake ninja-build pkg-config git wget p7zip-full extra-cmake-modules wayland-protocols tar gzip file appstream qttranslations5-l10n python3-pip python3-venv squashfs-tools"
 	if [ "$(dpkg --print-architecture)" = "$arch_deb" ]
 	then
 		pkgs="$pkgs build-essential"