[ +engeg ]
we no longer keep builds around forever. we got too many devices and have been around for too long that we had to start expiring content.
in your case, you're using a device that went EOL 3 years ago, and all of its builds have been removed now. you get a 403 error because of a GS implementation detail ... in reality, it's a 404.
$ gsutil ls gs://chromeos-dev-installer/board/daisy/
CommandException: One or more URLs matched no objects.
George: we changed chromeos-releases to retain the "last" build even for EOL devices. any reason to not do that for chromeos-dev-installer too ? it shouldn't add too much overhead. not sure if it's possible to recover this content at this point for older devices, but would help newer ones from falling off completely.
-mike