X68000 Expert w/26 pin SCSI motherboard connector

[EmpireStateHuman]

I bought what seems to be an X68000 Expert in a X68030 case a while back, and have successfully installed a PicoPSU and created a (v3) boot disk - so far so good. It came without a hard drive installed, but with a hard drive cable in place.

The problem I'm having is that I can't get the machine to recognize either a ZuluSCSI or BlueSCSI card:

- The SCSI cards are powered from the Pico PSU connector when either are plugged in, and flash at boot. They also appear to be correctly starting with their config files (setting x68000 mode) recognized

- I'm using the v3 drive images from https://nfggames.com/forum2/index.php?topic=7231.0

- I've checked with a multimeter, and the SCSI cable buzzes out correctly

On the assumption that this is an Expert and therefore a SASI device, I've installed the SxSI bootloader - but the machine starts up and refuses to recognize the drive.

One thing I've just realized - having checked the cable, both it and the board connector have 26 pins - which make it a *SCSI* cable, not a SASI. I'm wondering if this is really an Expert, although I don't seem to have an option to set a SCSI boot option  in SWITCH.X, and the machine otherwise seems to be working (ie the boards appear to be matched). Can anyone help?

[EmpireStateHuman]

Uh, so it appears from https://x68.aikotoba.jp/xvi/index.html that I have an *XVI* board in the bottom of the machine to go with the Expert mainboard.

I'm a bit surprised this combo works at all, but I guess the SCSI interface is there - is there any way to get a hard drive working without an extra SCSI card, though? Thanks!