@gemjuno I suggest you restart your kindle. I just upgraded from .28 to .30, rebooted, and I also couldn't connect over SSH via wifi even though I could ping it. I restarted the kindle again and it's fine now.
Not sure if this is related, but normally when you leave the usb cable in the kindle and restart, it'll be mounted after it starts up. But you if leave the cable in and restart from an update, it doesn't automatically mount. So something post-update makes the kindle behave differently.