Must be named .iso or .ISO. In the chapter you point from the manual: "You can use either a businesscard, a netinst or a full CD image (see Section 4.1, “Official Debian GNU/Linux CD-ROM Sets”). Be sure to select one that fits. Note that the “netboot mini.iso” image is not usable for this purpose." mini.iso is not suitable for this purpose. You tried only the mini.iso? -- Melhores cumprimentos/Best regards, Miguel Figueiredo http://www.DebianPT.org