Have you opened up the device? I know with iPads, that is easier said than done but in this case may give you a better idea. Stuck on Apple logo usually has something to do with the OS. Or as Dan mentioned, it could absolutely be the NAND storage.
That being said, "it's not a board problem until you're sure it's not a parts problem." I would want to at least look at the device's internals. This also smacks of potential liquid damage to me. Which will be much easier to spot if you look at the inside. But I also realize that's a lot of work for what may end up being. "Welp. The board is fried,"