diff --git a/README.adoc b/README.adoc
index d15e108..b977e16 100644
--- a/README.adoc
+++ b/README.adoc
@@ -35,7 +35,7 @@ RUN cp /workdir/etc/portage/make.conf /etc/portage/make.conf
 RUN eselect profile set default/linux/amd64/17.1
 RUN echo 'games-misc/cowsay' >> \
     /workdir/etc/portage/package.accept_keywords/cowsay
-RUN emerge --root=/workdir --quiet games-misc/cowsay
+RUN emerge --root=/workdir --buildpkg=y --usepkg --quiet games-misc/cowsay
 
 # Final image.
 FROM scratch