Not sure if anyone is using this now but I will be moving forward and today fixed 2 glaring issues in the gdrom emulation code.
This fix now more closely resembles how hardware works and if nothing else lets me run openMenu within lxdream-nitro.
With using actual Dreamcast bios

With using HLE bios emulation

Neither booted today due to a few issues
I'll be pushing a PR to https://gitlab.com/simulant/community/lxdream-nitro