Is that error message coming up in the AmigaDOS shell or in the X1000 firmware? If it's the firmware, my guess is that the drive isn't fully prepped correctly. I don't have any experience with the X1000, but my understanding is that the firmware is similar to that of the old XE AmigaONEs. You might need to install the second-lever booter to the drive, done through Media Toolbox. Is the boot partition marked as bootable? Is the correct file system in the disk's RDB? Other possibility is that the firmware is looking for the drive at one address and it's located at another. Is it plugged into the same port as the old drive? Is there any sort of jumper configuration you need to do to match the old drive?
