I recently switched to MI SCSI drivers on my 5000/200, with sources
compiled from yesterday.

xasc0 at tc0 slot 5 offset 0x0: NCR53C94, 25MHz, SCSI ID 7
scsibus0 at xasc0: 8 targets, 8 luns per target
xasc1 at tc0 slot 0 offset 0x0: NCR53C94, 25MHz, SCSI ID 7
scsibus1 at xasc1: 8 targets, 8 luns per target
scsibus0: waiting 2 seconds for devices to settle...
probe(xasc0:0:0): max sync rate 3.90Mb/s
sd0 at scsibus0 targ 0 lun 0: <DEC, RZ56     (C) DEC, 0400> SCSI1 0/direct fixed
sd0: 634 MB, 1632 cyl, 15 head, 53 sec, 512 bytes/sect x 1299174 sectors
probe(xasc0:1:0): max sync rate 3.90Mb/s
sd1 at scsibus0 targ 1 lun 0: <DEC, RZ56     (C) DEC, 0400> SCSI1 0/direct fixed
sd1: 634 MB, 1632 cyl, 15 head, 53 sec, 512 bytes/sect x 1299174 sectors
st0 at scsibus0 targ 5 lun 0: <DEC, TZK10, 03B8> SCSI2 1/sequential removable
st0: density code 0x0, 512-byte blocks, write-enabled
scsibus1: waiting 2 seconds for devices to settle...

the disks appear to work fine.  (yay!) tape is another story.
attempting an 'mt -f /dev/st0 status' results in:

/netbsd: st0(xasc0:5:0): xasc0: timed out [ecb 0xc001313c (flags 0x103, dleft 0, stat 0)], <state 1, nexus 0x0, phase(l 10, c 100, p 7), resid 0, msg(q 0,o 0) >
/netbsd: st0(xasc0:5:0): xasc0: timed out [ecb 0xc001313c (flags 0x103, dleft 0, stat 0)], <state 1, nexus 0x0, phase(l 10, c 100, p 7), resid 0, msg(q 0,o 0) >
/netbsd: st0(xasc0:5:0): xasc0: timed out [ecb 0xc001313c (flags 0x103, dleft 0, stat 0)], <state 1, nexus 0x0, phase(l 10, c 100, p 7), resid 0, msg(q 0,o 0) >
/netbsd: st0(xasc0:5:0): xasc0: timed out [ecb 0xc001313c (flags 0x1, dleft 0, stat 0)], <state 2, nexus 0xc001313c, phase(l 16, c 100, p 6), resid 0, msg(q 0,o 20) >
/netbsd: st0(xasc0:5:0): xasc0: timed out [ecb 0xc001313c (flags 0x103, dleft 0, stat 0)], <state 1, nexus 0x0, phase(l 10, c 100, p 7), resid 0, msg(q 0,o 0) >
/netbsd: st0: error 5 in st_load (op 1)

and if I try and read anything from the tape with dd, the machine panics
with "panic: xasc0: invalid state: 5"

this is repeatable.  I can arrange to make more swap available and
provide a full core dump / backtrace if anybody's interested.

-- 
  Aaron J. Grier | "Not your ordinary poofy goof." | agrier@poofygoof.com
  "Time Correct function allows automatically correcting slight variation
   of your key touching manner."  --  Roland MSQ-700 manual