All the original DMS files are available, contained in the firmware files downloaded by the Phathack DMS Tools when creating or repairing a DMS.
However, those files are not what a DMS needs to work in a Phatbox. There is an electronic signature written into the first 1MB of the original DMS drives, which is what an unhacked Phatbox needs to find on a DMS in order to work. This is why an original DMS is needed for hacking, as the Phatbox checks for the valid signature, allows the DMS to work, and then the hack goes to work to permanently disable the signature check.
In short, you need a working original DMS to hack your box.