Description of problem: On OSP8, we turned the ipxe_timeout of Ironic on. With this parameter, ipxe will retry a download on failure. This was enough to avoid a lot of problem with different hardware configurations. The patch for instack-undercloud is here: https://code.engineering.redhat.com/gerrit/#/c/72571/ I open this patch to be sure we won't forget to pull it on OSP9 too.
Jirka - Can you review the downstream 9 cherry pick mentioned in comment 2? Let me know if you need me to ping someone else for a second review.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHEA-2016-1599.html