diff --git a/Dockerfile b/Dockerfile
index d411671..3ffc190 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,8 @@
 #--------- Generic stuff all our Dockerfiles should start with so we get caching ------------
+ARG DISTRO=debian
 ARG IMAGE_VERSION=buster
 ARG IMAGE_VARIANT=-slim
-FROM debian:$IMAGE_VERSION$IMAGE_VARIANT
+FROM $DISTRO:$IMAGE_VERSION$IMAGE_VARIANT
 MAINTAINER Tim Sutton<tim@kartoza.com>
 
 # Reset ARG for version
diff --git a/README.md b/README.md
index a549217..73f310c 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,17 @@ Now edit ``71-apt-cacher-ng`` then do:
 docker build -t kartoza/postgis .
 ```
 
+### Building with alternative base distributions
+
+There are build args for `DISTRO` (=debian), `IMAGE_VERSION` (=buster)
+and `IMAGE_VARIANT` (=slim) which can be used to control the base image used
+(but it still needs to be Debian based and have PostgreSQL official apt repo).
+
+For example making Ubuntu 20.04 based build (for better arm64 support)
+```
+docker build --build-arg DISTRO=ubuntu --build-arg IMAGE_VERSION=focal --build-arg IMAGE_VARIANT="" -t kartoza/postgis .
+```
+
 ## Run
 
 
diff --git a/scenario_tests/datadir_init/test.sh b/scenario_tests/datadir_init/test.sh
index d46f2c6..aac6bab 100755
--- a/scenario_tests/datadir_init/test.sh
+++ b/scenario_tests/datadir_init/test.sh
@@ -8,7 +8,7 @@ source ../test-env.sh
 # Run service
 docker-compose up -d
 
-sleep 5
+sleep 30
 
 services=("pg-default" "pg-new" "pg-recreate")