A new driver update appears to be rolling out to the Surface Book — at least for those on the Slow and Fast Ring of the Windows Insider program. As seen in the screenshot below, the update simply brings a driver update for the Intel CSI2 Host Controller, and nothing else.
This new driver update is dated 5/17/2016 and is version number 30.10586.7076.2424, which is different from the production version that was last updated on May 9.
Without a changelog, it's not entirely clear what the driver update addresses. However, according to a tip, the update appears to address issues with the Surface Book and Surface Pro 4 resuming from Sleep.
The Intel CSI2 Host Controller is related to the camera and how it functions with the System Bus/Bridge, which is exactly why it may help with Resume issues on the latest Windows 10 builds and the Surface. At least from our experience, Windows Hello would loop, sometimes get stuck, and overall just be less reliable with the latest Redstone releases.
We can confirm that after the update Windows Hello is now fast and smooth again.
In any case, Surface Book and Surface Pro 4 users should be able to pull the update down through Windows Update now. Remember, this update is only visible for Slow and Fast Ring "Redstone" builds. And be sure to shout out in the comments if you notice any changes we may have missed!
Thanks to Jesse Cook on Twitter for the tip!