Thanks for Remko for his help to solve the fractional cylinder problem. But there is the second problem, the boot disk failure (see below << [B]) # but when booting via PXE (pxelinux.cfg/default) ... LABEL t KERNEL memdisk c=2 h=256 s=63 APPEND initrd=disk.img # the following things occur boot: t Loading memdisk Loading disk.img ...................................(16MB)......... Ready. MEMDISK 2.04 .... ... command line: initrd=disk.img harddisk c=2 h=256 s=63 BOOT_IMAGE=memdisk Disk is hard disk, 16128K CHS=2/256/63 <<<< [A] ... Loading boot sector... booting... SYSLINUX 2.04 welcome! boot: 1