diff --git a/Makefile b/Makefile
index 2a3e927..1dcdd70 100644
--- a/Makefile
+++ b/Makefile
@@ -29,7 +29,7 @@ raspi_base_buster.yaml: raspi_master.yaml
 	sed "s/__FIRMWARE_PKG__/raspi3-firmware/" | \
 	sed "s/__RELEASE__/buster/" |\
 	sed "s/__SECURITY_SUITE__/buster\/updates/" |\
-	sed "s/__FIX_FIRMWARE_PKG_NAME__/sed -i s\/raspi-firmware\/raspi3-firmware\/ \/etc\/systemd\/system\/rpi-reconfigure-raspi-firmware.service/" |\
+	sed "s/__FIX_FIRMWARE_PKG_NAME__/sed -i s\/raspi-firmware\/raspi3-firmware\/ \$${ROOT?}\/etc\/systemd\/system\/rpi-reconfigure-raspi-firmware.service/" |\
 	grep -v '__EXTRA_SHELL_CMDS__' > $@
 
 raspi_1_buster.yaml: raspi_base_buster.yaml