Would this make you reluctant to install such a jailbreak? Once installed, it should stay persistent until a major upgrade event like a service pack or Windows 8.2/9.0.
The reason for all this is because it turns out that what I'm trying to do can only be done on the C: drive. In order to do my exploit, I need raw write access to the disk sectors, and Windows does not allow writing to mounted filesystems to even applications running as Administrator. Only kernel drivers are allowed to do such raw writes, and I'm trying to become a kernel driver. They actually do this to defeat attempts to defeat driver signing. =)
A way to bypass this, of course, is to get to the drive when it's not mounted. You can't lock the C: drive for raw writing without booting to another OS installation, such as the recovery image.
This method is somewhat risky; I'd be doing sector-level writes to your primary disk partition. There would be a number of precautions to try to prevent writing to the wrong location, but there can never be guarantees that I don't screw up the code and delete your priceless documents.
How do you all feel about this?