If you delete a partition that doesn't have Mavericks on it, and leave behind the one that does, then yes you can boot into the one with Mavericks on it. I'm surprised this isn't entirely possible while you're booted into Mavericks.
What are you trying to do, anyway? Get rid of Yosemite? Get rid of BootCamp? Sorry, but the question wasn't too clear. -- You received this message because you are subscribed to the Google Groups "MacVisionaries" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/macvisionaries. For more options, visit https://groups.google.com/d/optout.
