Arch Linux

ExoDoom

Member

Registered: 2013-11-01

Posts: 39

GRUB2 Dual-booting issue

Hi all!

Last week, I had some problems with my hardware clock, and had to replace the motherboard's battery. After configuring some BIOS lost settings, I booted up my loyal Arch Linux and did some work. All worked like a charm. However, when I rebooted to Windows to play some games (some of them do not work on wine), Windows didn't load. As soon as I selected "Windows 7" from my GRUB, my pc restarted. It didn't even try to load Windows, it was like I had a reboot in my menuentry.

Of course, at first I blamed the replaced battery. All worked before that. But why? Then I started to search some information. After some digging, I had to admit my GRUB configuration was wrong. I had this before in my /etc/grub.d/40_custom (worked before the replacement, failed after it):

menuentry "Windows 7" --class windows {
    set root=(hd0,1)
    chainloader (hd0,1)+1
}

Now I have this:

menuentry "Windows 7" --class windows {
    insmod part_msdos
    insmod ntfs
    insmod search_fs_uuid
    insmod ntldr
    search --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 the_UUID_of_my_/dev/sda1
    ntldr /bootmgr
}

The latter works, but why the former doesn't? Is it supposed not to work on latest versions of GRUB (can't remember if I pacman -Syu'ed right after the battery replacement)? I know it's all well explained on the wiki, but I have been using the first configuration for years, without any issue.