Thanks to anyone for your feedback. Yes, the cable is connected correctly to the MB (blue connector), and to the drive (black connector, since drive is alone). I had also tried `hdparm -X69 /dev/hda` without success. And when I was getting the drive working correctly, then the day after, at machine startup, it would again ignore the UDMA-100 mode.
In fact, this seems to be caused by the kernel itself: I've checked in the linux-kernel mailing list archives, and found out that other people had the same problems with the Promise stuff. To solve this, just add "idex=ata66" to the kernel parameters in lilo or grub (where x is the ID of the HDD on which to force UDMA-66/100): it will bypass cable detection and force UDMA-100 mode. Now everything is working fine :-) Thanks again to everybody. Cheers, Dominique -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]