I've added a second Disk to my system and copied my linux-installation + grub on it. My system contains 2 disks now: hd0: sda5: linuxhd1: (old system with dualboot)sdb2: windowssdb5: linuxIf I boot from hd1 (Bios boot menu or unplug hd0), windows starts immediatly, but if I boot from hd0 and select to boot from windows, it only shows me a black screen with a blinking courser. hd0/grub.cfg (doesn't work)menuentry 'Windows 7 (loader) (/dev/sdb1)' --class windows --class os $menuentry_id_option 'osprober-chain-9C567F24567EFE78' {        insmod part_msdos        insmod ntfs        set root='hd1,msdos1'        if [ x$feature_platform_search_hint = xy ]; then          search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1  9C567F24567EFE78        else          search --no-floppy --fs-uuid --set=root 9C567F24567EFE78        fi        parttool ${root} hidden-        chainloader +1}hd1/grub.cfg (works)menuentry 'Windows 7 (loader) (/dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-chain-9C567F24567EFE78' {    insmod part_msdos    insmod ntfs    set root='hd0,msdos1'    if [ x$feature_platform_search_hint = xy ]; then      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1  9C567F24567EFE78    else      search --no-floppy --fs-uuid --set=root 9C567F24567EFE78    fi    parttool ${root} hidden-    chainloader +1}PS: My system is kinda old now (athlon x4) with a normal bios and not UEFI. Any ideas, or how can I get more debug information? Or is there some limitation and windows always needs to be installed on first harddrive? (Even in 2016)Solution: menuentry 'Windows 7 cust' --class windows --class os $menuentry_id_option 'osprober-chain-9C567F24567EFE78' {        insmod part_msdos        insmod ntfs        set root='hd1,msdos1'        if [ x$feature_platform_search_hint = xy ]; then          search --no-floppy --fs-uuid --set=root --hint-bios=hd1,msdos1 --hint-efi=hd1,msdos1 --hint-baremetal=ahci1,msdos1  9C567F24567EFE78        else          search --no-floppy --fs-uuid --set=root 9C567F24567EFE78        fi###parttool ${root} hidden-        drivemap -s (hd0) ${root} ### intern disk swap        chainloader +1}
Windows won't boot from hd1
linux;windows;grub2;dual boot
Booting windows with grub on a non-first drive is a bit tricky: you will have to swap your disks:If you have installed DOS (or Windows) on a non-first hard disk, you have to use the disk swapping technique, because that OS cannot boot from any disks but the first one. The workaround used in GRUB is the command drivemap (see drivemap), like this:  drivemap -s (hd0) (hd1)More details at https://www.gnu.org/software/grub/manual/html_node/DOS_002fWindows.html#DOS_002fWindows