Lenny on E4500, esp_scsi won't detect disks

[Mr Ian Primus <ian_primus@yahoo.com>]

I'm attempting to install Debian on my Sun Enterprise 4500. I've downloaded the Sparc netinst (5.0.4), cut the disc and booted the Sun from it. All seems to go well, but then it complains it can't find the CDROM. By manually telling it to use /dev/cdrom, it'll continue, but as soon as it goes to detect disks it's all over. The console spews esp0 errors, the scsi bus gets reset a couple times, and then it eventually hangs up the bus. After that, it can't even read the CDROM any more. 

Watching the console as things are booting, I can see that the esp_scsi module does indeed find the CDROM, and the hard disk. A cat of /proc/scsi/scsi lists the devices on the bus (just the internal DVDROM drive and the external hard disk), and cat of /proc/partitions shows sda. It just seems that as soon as it tries to "detect disks", then it loses it's brains.

lsmod reports that esp_scsi and sun_esp are both loaded. I can't remove/reinsert the module because rmmod isn't a valid command from the installer disc.

Before booting from the CD, OpenBoot can see the hard drive and DVDROM from probe-scsi, and the devices are connected and terminated properly.

Any ideas? 

-Ian