Sorry for the late reply!
I'm not entirely sure as to how the scripts work, honestly. I've had a look through them, and there's a long list of files in the deblob-4.2 file: that would seem to suggest that the blob locations are hard-coded, but it's not proof. I've asked at the GNU Linux-Libre mailing list, so hopefully somebody there will be able to help (presuming the message ever makes it through...).
