when running emerge --update --keep-going --tree @system @world with portage itself in the list of updates, portage fail-exits with "invalid resume list" after updating portage. this bug seems in for longer, i've seen it before. i'm on x86, testing.
There is nothing more than "invalid resume list"?
This should be fixed by the changes from bug #390819: http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=d3f704a425a50b5cfa997a25866929b30f1b7d0f