I have an 800 personality board that provides Phi2 in the left cartridge area and allows a 16K OS. (Not Icognito.) Is there a MyBios version that will run as a 16K OS and allow the MyIDE + Flash or MyIDE-II to work? My major interest is the MyDos hard drive.

There is no 800 MyBIOS at the moment.

All MyBIOS versions are XL orientated and disable joysticks 3/4 as default.
If that is no issue to you, just use the matching 16k .ROM file

But there is no need to use the ROM version, the soft-OS versions from the cartridge itself should work nicely too.

Grtz,
Sijmen.