To format the hard disk you need to use the CPM based system tools. To use the tools you need to patch a CPM+ disc so that it recognises the hard disk.
The disc format appears to be * CPM/AMSDOS based, with 0x0e5 as the format data byte.
* 512 bytes per sector (possibly defined with jumpers)
* 17 sectors per cylinder (possibly defined with jumpers)