diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 00000000..eae2fec0
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,2 @@
+.cosa
+target
diff --git a/ci/prow/Dockerfile b/ci/prow/Dockerfile
index 8ba6d4ee..18cf0c6b 100644
--- a/ci/prow/Dockerfile
+++ b/ci/prow/Dockerfile
@@ -1,12 +1,19 @@
-FROM registry.svc.ci.openshift.org/coreos/cosa-buildroot:latest as builder
+FROM registry.ci.openshift.org/coreos/cosa-buildroot:latest as builder
 WORKDIR /src
 COPY . .
 RUN ./ci/build.sh && make install DESTDIR=/cosa/component-install
+RUN make -C tests/kolainst install DESTDIR=/cosa/component-tests
 # Uncomment this to fake a build to test the code below
 # RUN mkdir -p /cosa/component-install/usr/bin && echo foo > /cosa/component-install/usr/bin/foo
 
-FROM registry.svc.ci.openshift.org/coreos/coreos-assembler:latest
+FROM registry.ci.openshift.org/coreos/coreos-assembler:latest
 WORKDIR /srv
-# Install our built binaries as overrides for the target build
-COPY --from=builder /cosa/component-install /srv/overrides/rootfs/
+USER root
+# Copy binaries from the build
+COPY --from=builder /cosa /cosa
+# Merge them to the real root since we're used at compose time
+RUN rsync -rlv /cosa/component-install/ /
+# Merge installed tests
+RUN rsync -rlv /cosa/component-tests/ /
 COPY --from=builder /src/ci/prow/fcos-e2e.sh /usr/bin/fcos-e2e
+USER builder
diff --git a/ci/prow/fcos-e2e.sh b/ci/prow/fcos-e2e.sh
index f0b1dc01..6365ad84 100755
--- a/ci/prow/fcos-e2e.sh
+++ b/ci/prow/fcos-e2e.sh
@@ -3,9 +3,13 @@ set -xeuo pipefail
 
 # Prow jobs don't support adding emptydir today
 export COSA_SKIP_OVERLAY=1
-gitdir=$(pwd)
+# And suppress depcheck since we didn't install via RPM
+export COSA_SUPPRESS_DEPCHECK=1
+ls -al /usr/bin/rpm-ostree
+rpm-ostree --version
 cd $(mktemp -d)
-cosa init --force https://github.com/coreos/fedora-coreos-config/
+cosa init https://github.com/coreos/fedora-coreos-config/
+rsync -rlv /cosa/component-install/ overrides/rootfs/
 cosa fetch
 cosa build
-cosa kola run 'ext.*'
+cosa kola run 'ext.rpm-ostree.*'
diff --git a/tests/kolainst/kolainst-build.sh b/tests/kolainst/kolainst-build.sh
index 5f073c5b..d4d8ec76 100755
--- a/tests/kolainst/kolainst-build.sh
+++ b/tests/kolainst/kolainst-build.sh
@@ -3,7 +3,7 @@
 # to the kola tests as data/, so we don't need to rpmbuild.
 set -euo pipefail
 dn=$(cd "$(dirname "$0")" && pwd)
-topsrcdir=$(git rev-parse --show-toplevel)
+topsrcdir=$(cd $dn/../.. && pwd)
 commondir=$(cd "$dn/../common" && pwd)
 export topsrcdir commondir
 . "${commondir}/libtest.sh"