diff --git a/files/chroot_build.sh b/files/chroot_build.sh
index 6e22750..b675e67 100755
--- a/files/chroot_build.sh
+++ b/files/chroot_build.sh
@@ -115,7 +115,8 @@ apt-get install -y -qq -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="
   dkms \
   iwd \
   apple-t2-audio-config \
-  dmg2img
+  dmg2img \
+  apple-firmware-script
 
 echo >&2 "===]> Info: Change initramfs format (for grub)... "
 sed -i "s/COMPRESS=lz4/COMPRESS=gzip/g" "/etc/initramfs-tools/initramfs.conf"