Here's that machine with dmesg: http://vax.zia.io/WOW! The SCSI/FLASH adapter works in the VLC? I tried them in a 4000/90, and didn't have any luck.
For some odd reason I could not get it to work at all at SCSI ID 0, but it works fine at ID 1. Also, setting boot to dka1 didn't work, but dka100 does. I couldn't boot off of any LUN but the 0th.
My 4000/90a has an IDE disk on a Acard SCSI-IDE adapter which works very well.
John