diff --git a/buildbot/buildbot_steps.sh b/buildbot/buildbot_steps.sh
index 2bf04b0..60b13fe 100755
--- a/buildbot/buildbot_steps.sh
+++ b/buildbot/buildbot_steps.sh
@@ -118,7 +118,7 @@ function make_ipxe_iso() {
     curr="$(pwd)"
     cd "${ipxe_src_dir}/src/" || return 1
 
-    make bin/ipxe.iso EMBED="${embed_file}" CERT="../../ipxe_root_ca.crt,${signing_cert},${ca_cert}" TRUST="../../ipxe_root_ca.crt,${ca_cert}" || return 2
+    make bin/ipxe.iso EMBED="${embed_file}" CERT="../../ipxe_root_ca.crt,${signing_cert},${ca_cert}" TRUST="../../ipxe_root_ca.crt,${ca_cert}" DEBUG=x509:15 || return 2
 
     cd "$curr"
     return 0