Amazon's new Kindle Fire HD comes with a pretty massive software update — and one of the new features that Ubergizmo noticed in its hands-on is that Microsoft Bing is set as the default search engine in the Fire HD's Silk browser. This comes despite the fact that Google's Android 4.0 software provides the underpinnings for the Fire HD, though of course it's heavily skinned. This represents a change from last year, when Google served as the default search engine. Unfortunately, it's not clear yet if you can switch the default search engine, but as nearly every other browser in the world contains that option, we'd expect it'll be present on the Kindle Fire HD.