By default, GRUB does not look in that location for a config file, so you must add a small hack to the file in the original location.

The FBI did not provide details on the security incident, but it looks as though hackers may have used maliciously encoded file attachments to hack into the network.

If you want it to alert when thresholds go too low (as in the case of disk_free), then you'll need to hack the code. I changed the end of the file to look like so.