diff --git a/build.sh b/build.sh
index 3e04204..5c3539f 100755
--- a/build.sh
+++ b/build.sh
@@ -137,6 +137,9 @@ do
 	esac
 done
 
+export PI_GEN=${PI_GEN:-pi-gen}
+export PI_GEN_REPO=${PI_GEN_REPO:-https://github.com/RPi-Distro/pi-gen}
+
 if [ -z "${IMG_NAME}" ]; then
 	echo "IMG_NAME not set" 1>&2
 	exit 1
diff --git a/scripts/common b/scripts/common
index 05198b7..9db903e 100644
--- a/scripts/common
+++ b/scripts/common
@@ -96,7 +96,7 @@ export -f on_chroot
 update_issue() {
 	local GIT_HASH
 	GIT_HASH=$(git rev-parse HEAD)
-	echo -e "Raspberry Pi reference ${IMG_DATE}\nGenerated using pi-gen, https://github.com/RPi-Distro/pi-gen, ${GIT_HASH}, ${1}" > "${ROOTFS_DIR}/etc/rpi-issue"
+	echo -e "Raspberry Pi reference ${IMG_DATE}\nGenerated using ${PI_GEN}, ${PI_GEN_REPO}, ${GIT_HASH}, ${1}" > "${ROOTFS_DIR}/etc/rpi-issue"
 }
 export -f update_issue