There is at one report of an OpenRD ultimate that would not boot with the 2016.09~rc2 version of u-boot in debian. Uploaded 2016.09+dfsg-1 to unstable a few days ago. Would you be able to confirm if OpenRD variants that you have still work with the version in unstable?
https://bugs.debian.org/837629 If it can't be fixed, I'll likely remove OpenRD ultimate at some point so that u-boot 2016.09 can migrate to stretch... but it would be more ideal to fix it, of course! :) live well, vagrant
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