I've confirmed this fix for hardy. I wrote a copy of the 8.04.4 candidate server ISO to a USB stick using the lucid version of usb-creator, then booted it editing the kernel commandline to remove 'cdrom-detect/try-usb=true' and confirmed that the installer failed when looking for the CD. Then I booted again without editing the kernel commandline, and the installer gets past this point just fine and begins loading installer components from the USB stick.
I've confirmed this fix for hardy. I wrote a copy of the 8.04.4 candidate server ISO to a USB stick using the lucid version of usb-creator, then booted it editing the kernel commandline to remove 'cdrom- detect/ try-usb= true' and confirmed that the installer failed when looking for the CD. Then I booted again without editing the kernel commandline, and the installer gets past this point just fine and begins loading installer components from the USB stick.