Cannot install 6.0-RC1 on Promise SX4060 (DANGER WILL ROBINSON)

[Mark Kirkwood]

Hi, I am trying to install 6.0-RC1 on a system with a Promise SX4060 
(PDC20621) + 4 Maxtor ATA-133 drives (6E040L0). The mobo is a Tyan 
Thunder LE (S2510).

The card appears to be detected ok (tho the exact text rushes past 
before I can read it completely), but the drive probing fails completely:

ad4 : FAILURE - SET FEATURES TRANSFER MODE timed out.
ad4 : FAILURE - SET FEATURES RCACHE timed out.
ad4 : FAILURE - SET FEATURES WCACHE timed out.
ad4 : FAILURE - SET FEATURES SET_MULTI.
ad4 : FAILURE - READ timed out (LBA = 80293185)
ad4 : FAILURE - READ retrying (0 retries left) LBA = 0
..
ad4 : req = 0xc3b78960 SET FEATURES SET TRANSFER MODE semaphore timeout 
!!DANGER WILL ROBINSON!!
..
..
(hand copied as I don't have a serial console)

Note that using a TX2000 on this machine (with the same drives) works 
flawlessly.

Any suggestions about how to proceed (I would like to get this going)

Cheers

Mark