diff --git a/build.sh b/build.sh
index 4b19c01..1abdc2c 100755
--- a/build.sh
+++ b/build.sh
@@ -9,5 +9,5 @@ PS4=" $ "
 # way to go.
 
 set -x
-exec env -i NIX_PATH="nixpkgs=channel:nixos-19.09" nix-build \
+exec env -i NIXPKGS_ALLOW_UNFREE=1 NIX_PATH="nixpkgs=channel:nixos-19.09" nix-build \
   system.nix -A config.system.build.sdImage "$@"