diff --git a/.buildbot.sh b/.buildbot.sh
index fb68862..1e8dd9f 100644
--- a/.buildbot.sh
+++ b/.buildbot.sh
@@ -22,7 +22,7 @@ cd ..
 # FIXME: We should test all optimisation levels.
 # https://github.com/ykjit/ykcbf/issues/9
 YK_BUILD_TYPE=debug CFLAGS=-O0 make bf_base
-YK_BUILD_TYPE=debug CFLAGS=-O0 make bf_simple_yk
-YK_BUILD_TYPE=debug CFLAGS=-O0 make bf_simple2_yk
+YKD_NEW_CODEGEN=1 YK_BUILD_TYPE=debug CFLAGS=-O0 make bf_simple_yk
+YKD_NEW_CODEGEN=1 YK_BUILD_TYPE=debug CFLAGS=-O0 make bf_simple2_yk
 
-cd lang_tests && cargo test
+cd lang_tests && YKD_NEW_CODEGEN=1 cargo test
diff --git a/.buildbot_dockerfile_debian b/.buildbot_dockerfile_debian
index 7807ffb..5ebb7ce 100644
--- a/.buildbot_dockerfile_debian
+++ b/.buildbot_dockerfile_debian
@@ -3,7 +3,7 @@ ARG CI_UID
 RUN useradd -m -u ${CI_UID} ci
 RUN apt-get update && \
 apt-get -y install clang-15 make curl procps file git cmake python3 \
-    libtinfo-dev libzip-dev mold ninja-build
+    libtinfo-dev libzip-dev mold ninja-build gdb
 WORKDIR /ci
 RUN update-alternatives --install /usr/bin/cc cc /usr/bin/clang-15 999
 RUN update-alternatives --set cc /usr/bin/clang-15