diff --git a/sdk_container/src/third_party/coreos-overlay/.github/workflows/setup-flatcar-sdk.sh b/sdk_container/src/third_party/coreos-overlay/.github/workflows/setup-flatcar-sdk.sh
index f1f09b62d3..6d5b8ea700 100755
--- a/sdk_container/src/third_party/coreos-overlay/.github/workflows/setup-flatcar-sdk.sh
+++ b/sdk_container/src/third_party/coreos-overlay/.github/workflows/setup-flatcar-sdk.sh
@@ -17,9 +17,32 @@ mkdir -p ~/flatcar-sdk
 pushd ~/flatcar-sdk || exit
 cork create || true
 
+sudo tee "./chroot/etc/portage/repos.conf/coreos.conf" <<EOF
+[DEFAULT]
+main-repo = portage-stable
+
+[gentoo]
+disabled = true
+
+[coreos]
+location = /mnt/host/source/src/third_party/coreos-overlay
+
+[portage-stable]
+location = /mnt/host/source/src/third_party/portage-stable
+EOF
+
 # /var under the chroot has to be writable by the runner user
 sudo chown -R runner:docker ~/flatcar-sdk/chroot/var
 
+function enter() ( exec cork enter -- $@ )
+
+# To be able to generate metadata, we need to configure a profile
+# /etc/portage/make.profile, a symlink pointing to the SDK profile.
+enter sudo eselect profile set --force "coreos:coreos/amd64/sdk"
+
+# make edb directory group-writable to run egencache
+enter sudo chmod g+w /var/cache/edb
+
 git -C src/third_party/coreos-overlay reset --hard github/flatcar-master
 git -C src/third_party/coreos-overlay config user.name 'Flatcar Buildbot'
 git -C src/third_party/coreos-overlay config user.email 'buildbot@flatcar-linux.org'