Vhd interface for victor hc90/95

The video issue is not related to VHD card but something with by Victor HC-7.
My VHD card for Victor HC-9x and VHD cartridge module (in Victor HC-7) seems to work with games that have game code on cassette.

We are only lacking full VHD implementation to play games that have game code on VHD disk itself. I have hunch that maybe IF-7900 shares same 8049 chips and roms as IF-C9C. So dumping of the ROM from IF-7900 card or from IF-C9C would help. That dumping shuold be easy task (and no harm is done to cartridge) to owners of that card. But somehow the owners are not interest to share that...