Hello,
I have had lots of 2000's over the years and still have a couple. I never could get my 2091 with any rom version including 7.0 to work properly with an internal hard drive and SCSI CD-Rom drive. I always had problems with the CD at cold boot up. I seem to remember even the Guru Rom that I had didn't solve all the problems. I even updated the SCSI chip to a rev 8 :-).
My friend ran a BBS for years on a 2000 with an a couple Internal Hard Drives and a stack of CD-Roms in an external case with a A2091 and his worked perfectly. Perhaps I never got the termination worked out properly. I just sold my 2091 Guru Rom for about $20.00 a while back on eBay, sorry.
The only 2000 I have that works perfectly with an Internal CD Drive uses the controller on the Blizzard 040 card.
I would be interested if you find the Magic Combo that makes this work, as I still have some hardware in storage.
Good Luck,
Jeff