[cctalk] Rainbow 100 and Univation Hard Disk

I have a Rainbow 100A with the Univation hard disk. Works (wow!), but the Univation HDD controller was not DEC compatible and you have to boot from a floppy to get the disk drivers loaded. And of course, the 100A ROMs didn't support any kind of hard disk, DEC or otherwise. Did anybody ever make an updated ROM image for the 100A that supported booting from the Univation directly? I think the 100A used 2716 EPROMs, and it'd be easy enough to burn some new ones. And is there any surviving documentation for the Univation? Bitsavers seems to have nothing. Thanks!