| View previous topic :: View next topic |
| Author |
Message |
CyberMuz
n00b
Joined: 03 Jan 2012
Posts: 53
|
 Posted: Sun Jan 19, 2014 12:00 pm Post subject: Grub2 break Windows 7 mbr (dual boot) |
 |
|
I have Gento and Windows 7 on my machine, i have recently upgraded to GRUB2 and after the grub install i can't boot to windows.
THis is my setup:
| Code: |
fdisk -l
Disk /dev/sda: 250.1 GB, 250059350016 bytes, 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x77777777
Device Boot Start End Blocks Id System
/dev/sda1 * 63 102398309 51199123+ 7 HPFS/NTFS/exFAT
/dev/sda2 102398371 488392064 192996847 f W95 Ext'd (LBA)
/dev/sda5 102398373 225279494 61440561 7 HPFS/NTFS/exFAT
/dev/sda6 225279558 389110364 81915403+ 7 HPFS/NTFS/exFAT
/dev/sda7 389113856 390137855 512000 83 Linux
/dev/sda8 390139904 482414591 46137344 83 Linux
/dev/sda9 482416640 488392064 2987712+ 82 Linux swap / Solaris
|
In grub.cnf i have added the following:
| Code: |
menuentry "Windows 7 BIOS/MBR" {
insmod part_msdos
insmod ntldr
insmod ntfs
ntldr (hd0,msdos1)/bootmgr
}
|
When I select the Windows 7 in grub menu I get the following error
[IMG]http://i.imgur.com/HlBKM2t.jpg[/IMG]
To fix Windows boot I have to insert the Win installation directory and run BootRec.exe /fixmbr (from command prompt) but then system boots directly to windows (no grub). If I reinstall grub then Windows is not working. :-/
Any idea how I can fix this issue? |
|
| Back to top |
|
 |
creaker
l33t
Joined: 14 Jul 2012
Posts: 651
|
| Posted: Sun Jan 19, 2014 12:28 pm Post subject: |
|
|
| It is strange enough that you managed to install grub2. You should get an error during grub2-install. Free space before first partition isn't enough to fit grub2 boot image. Your partition should start at 2048th sector, not at 63th. Probably grub2-install overwrites Windows files and leads to Windows boot breakage. |
|
| Back to top |
|
|
CyberMuz
n00b
Joined: 03 Jan 2012
Posts: 53
|
| Posted: Sun Jan 19, 2014 3:24 pm Post subject: |
|
|
Grub2 install doesn't report any errors. I had sabayon installed on this machine that also used Grub2 and it could boot to WIndows without any problem. I delete sabayon and installed Gentoo on the same partition, I didn't change anything on Windows partitions.
Is there a way to have dual boot with grub2 without rearranging the partitions? |
|
| Back to top |
|
|
Logicien
Veteran
Joined: 16 Sep 2005
Posts: 1555
Location: Montréal
|
| Posted: Sun Jan 19, 2014 11:00 pm Post subject: |
|
|
It's hard to predict the Windows behavior when something change in the partition tables and/or when you format one of them. creaker point that the first sector of the first partition do not start at 2048. I see that the extended partition is not the fourth one. If the C partition come after, Windows can feel any change more easily.
I dont know the exact cause of the Windows boot incapability, you can make a search about Windows problems related with Grub. One thing I did to resolv a problem I had to bualboot Windows with Gentoo in EFI mode with Grub2, was to remove Windows. 
The way things are going in DOS/MBR and GPT partition tables and in BIOS and EFI modes, it is easier to use a Windows bootloader to boot Windows/Linux than a Linux bootloader to do it.
On quetion, if the first partition is the Windows boot partition, have you try to make Grub only chainload to the first partition like this
| Code: | menuentry "Windows 7 BIOS/MBR" {
root (hd0,msdos1)
chainloader +1
boot
} |
Note that you should not edit the /boot/grub/grub.cfg file directly, but use the /etc/grub.d/40_custom file to make an entry instead and than
| Code: | | grub2-mkconfig -o /boot/grub/grub.cfg |
_________________
Paul
Last edited by Logicien on Mon Jan 20, 2014 3:40 pm; edited 2 times in total |
|
| Back to top |
|
|
cwr
Veteran
Joined: 17 Dec 2005
Posts: 1969
|
| Posted: Mon Jan 20, 2014 8:50 am Post subject: |
|
|
That's the reason I boot _through_ Windows to a grub partition - Windows is
pretty neurotic, especially on my laptops. It adds about 10 seconds to the
boot time, but it's worth it for peace of mind and easy setup (given a separate
grub boot partition).
Google for EasyBCD to get an idea of what's possible.
Good luck - Will |
|
| Back to top |
|
|
|
Installing Gentoo
