It seems my katana unit's hard drive has finally died, as only the debug adapter is recognized by the PC and the last thing GD workshop told me was that there was an error to do with the FAT system on the drive... Seeing as it can't be detected I can't really reformat it, so I'm going to try taking the unit apart and connecting the drive directly, if it uses the same scsi connectors as I have for the actual unit itself. But what hard drives can I use to replace it? The unit seems stuck in emulation mode and I can hear the hard drive power up when the unit powers up, but it will hang at the Dreamcast logo trying to load the last project on boot. EDIT: (This might have been better in the repair and conservation forum...)
You can open it up and make sure the SCSI connection from the drive hasn't come loose on the sub board it connects to. Seems to be a common issue. Also you can get a 2.5" SATA to 3.5" SCSI enclosure that will allow you to use modern drives. The enclosures are 200-300$ but finding a suitable SCSI drive will be very expensive anyways and at least you could reuse the enclosure if the SATA drive dies on down the road. Check out the old katana threads on here for specifics of what drives will work.
Any old 9.1GB SCSI drive should do I reckon. I've got a spare IBM one from an old server if you're nearby in the UK, you can have it for free, I'd even re-image it from my katana kit if there's files that you need for it to work. Otherwise, ebay. You can pick them up for £10 a pop probably.
Hey, thanks for the offer! I did get it fixed though, the thread has been weird since it got moved to the repair forum.
Another option is the SCSI2SD board, which works perfectly as a drop in replacement: http://www.codesrc.com/mediawiki/index.php?title=SCSI2SD
2-3 weeks before your answer, I decided to try it out & ordered one. Received without problems, updated the firmware, changed some settings (the size of the SD card + selected SCSI-2 instead of the default SCSI1)... and everything seems to work fine with my devkit indeed Thanks again for the tip !