You can attempt to upgrade whichever drivers you want, but there are no 100% guarantees. Before they released 1.9.1 with the camera working for m002 I was running 1.7.4 with some updated 1.9.0 drivers. The mma driver caused my touchscreen not to respond, so I stuck with the 1.7.4 version. This seemed to be due to a difference between either the kernel and driver or the userspace and driver of the versions. There really isn't a risk of bricking based on the drivers because you can just reflash with the working drivers, but understand that anytime you flash your device something could go wrong during the uboot and wload portion which would brick the device (this is a risk with any stock firmware too and not just cutsom ones). I'm sure if you wait for Roger to get better he'll put out a new Vestinious build based on 1.9.1