Richard, we have just installed a CentOS 5.5 on 320G6 with B110i controller. As you correctly said, the CentOs shows both devices while booting w/o dd. However, as we have found, contrary to what is said in release notes for the controller DD, you must not dd it, however, just unzip it and place the .dd file on your flash disk, preferrably formatted in plain FAT16(vfat). After that, boot up your CentOS install disk with 'linux dd' option. CentOs will accept the dd file from the flash disk w/o further complaints. Note though, that even though the CentOs will install over the RAID1+0 virtual volume, sda and sdb will still be shown in the device tree, although the B110i will correcly write to both devices. Anton