PC-9801DA Bios help?

[LowDefAl]

I'm trying to change the GDC on my DA. The DA removed most of the DIP switches and moved them to the bios. However I can't save any changes in the Bios, the keyboard commands displayed on screen are just for up, down, left right and changing the page as well as escape. However simply changing the entry doesn't work, moving to another page resets the selection and pressing esc doesn't save.  I see the 9821 bios has a command to save at the bottom of each page, but there is nothing on the DA.



It is possible that the joystick port is grounding on the case/other ports and causing the issue. I have previously observed that the GDC error on some games only appears intermittently and this has been caused by this sort of grounding. The port isn't well attached and actually needs to be removed so I can fit the SxSi riser and I have an -86 board on the way which means the port is being removed anyway.   

Either way, I'd like to confirm the bios operation for future reference.