Storage system should handle other drive configurations
Right now, the storage code assumes USB storage is sda1 and only sda1. If a second drive is inserted, it probably does something confusing and incorrect. If, for any reason, the drive is not sda or it's not partitioned with sda1 covering the usable storage, it also breaks. It should handle alternate situations better, if only as errors.
Also, the pc build boots from sda. There are checks in storaged that happen to exclude it (already mounted, etc.), but we should have a more explicit policy and mechanism.