Solved Windows 7 & Centos 7 Dual Boot Issues - Grub2 BOOTMGR missing message

[os7tensed]

Windows 7 & Centos 7 Dual Boot Issues - Grub2 BOOTMGR missing message

Dear All,

I was having windows 7 and centos 6.8 dual boot working fine. I upgraded to centos 7. All my problem starts from this point onwards.

Some analysis which i have done till now:

1. Windows 7 has boot partition. I do not have it. (Accidental deleted or didn't had, i am not sure)
2. Centos boot partition of type xfs is there in the drive.
3. I already have 4 partitions on my disk, so i cannot have a new one.

Options available to me:
1. Create a boot partition of type ISO9660, which can be shared between linux and windows.
2. Migrate my Centos boot partition to this new ISO9660 partition. (how to do that, i still do not know)
3. Install windows 7 boot files on this partition, using windows disk? (not sure how will i do that)
OR
4. I can still achieve dual boot without doing the madness explained in 1-3. How, i don't know. Are there any tools and scripts which can confirm that?

Thanks Kapil.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

This is my laptop. 1 disk and multiple partitions scenario.

fdisk -l
-------------
Disk /dev/sda: 320.1 GB, 320072933376 bytes, 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk label type: dos
Disk identifier: 0x009304de

Device Boot Start End Blocks Id System
/dev/sda1 * 209717248 211814399 1048576 83 Linux
/dev/sda2 206848 209717247 104755200 7 HPFS/NTFS/exFAT
/dev/sda3 211814400 419432447 103809024 8e Linux LVM
/dev/sda4 419432448 625141759 102854656 5 Extended
/dev/sda5 436215808 625141759 94462976 7 HPFS/NTFS/exFAT

Partition table entries are not in disk order

Disk /dev/mapper/cl-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk /dev/mapper/cl-swap: 8321 MB, 8321499136 bytes, 16252928 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk /dev/mapper/cl-home: 44.3 GB, 44283461632 bytes, 86491136 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
------------------------------------------------------------------------------------------------------------------------------------
After providing following entries in /etc/grub.d/40_custom

cat <<EOF
menuentry "Windows 7" {
insmod part_msdos
insmod ntfs
set root='(hd0,msdos2)'
chainloader +1
ntldr /bootmgr
}
EOF

grub2-makeconfig doesn't recognize Windows as OS. I believe this is because in /boot there is nothing for windows.

Due to this in boot prompt i get Windows 7 option. When i try it, it tells bootmgr missing.

I also read about windows 7 having a boot partition. But i am sure i was not having one. Also how can i validate the same i.e. That /dev/sda2 contains the boot partition, or boot partition is deleted ?

Would be grateful, if some direction can be shared.

UPDATE 1:
Boot Info Script Output.
-----------------------------------------------------------------------------------------------
Boot Info Script 0.61 [1 April 2012]


============================= Boot Info Summary: ===============================

=> Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of
the same hard drive for core.img, but core.img can not be found at this
location.

sda1: __________________________________________________________________________

File system: xfs
Boot sector type: -
Boot sector info:
Operating System:
Boot files: /grub2/grub.cfg

sda2: __________________________________________________________________________

File system: ntfs
Boot sector type: Windows Vista/7: NTFS
Boot sector info: No errors found in the Boot Parameter Block.
Operating System: Windows 7
Boot files: /Windows/System32/winload.exe

sda3: __________________________________________________________________________

File system: LVM2_member
Boot sector type: -
Boot sector info:

sda4: __________________________________________________________________________

File system: Extended Partition
Boot sector type: Unknown
Boot sector info:

sda5: __________________________________________________________________________

File system: ntfs
Boot sector type: Windows Vista/7: NTFS
Boot sector info: According to the info in the boot sector, sda5 starts
at sector 2048.
Operating System:
Boot files:

cl-root': ______________________________________________________________________

File system:
Boot sector type: Unknown
Boot sector info:
Mounting failed: mount: unknown filesystem type ''

cl-home': ______________________________________________________________________

File system:
Boot sector type: Unknown
Boot sector info:
Mounting failed: mount: unknown filesystem type ''
mount: unknown filesystem type ''

cl-swap': ______________________________________________________________________

File system:
Boot sector type: Unknown
Boot sector info:
Mounting failed: mount: unknown filesystem type ''
mount: unknown filesystem type ''
mount: unknown filesystem type ''

============================ Drive/Partition Info: =============================

Drive: sda _____________________________________________________________________

Disk /dev/sda: 320.1 GB, 320072933376 bytes, 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Partition Boot Start Sector End Sector # of Sectors Id System

/dev/sda1 209,717,248 211,814,399 2,097,152 83 Linux
/dev/sda2 * 206,848 209,717,247 209,510,400 7 NTFS / exFAT / HPFS
/dev/sda3 211,814,400 419,432,447 207,618,048 8e Linux LVM
/dev/sda4 419,432,448 625,141,759 205,709,312 5 Extended
/dev/sda5 436,215,808 625,141,759 188,925,952 7 NTFS / exFAT / HPFS


"blkid" output: ________________________________________________________________

Device UUID TYPE LABEL

/dev/mapper/cl-home 443fb897-fc16-4977-b1f0-e3208d6b2957 xfs
/dev/mapper/cl-root 360f5e2c-f0a9-474d-ba69-7a0ab297e59e xfs
/dev/mapper/cl-swap d7630c88-df11-4a65-befc-2b0ea843a3b7 swap
/dev/sda1 f1ed9afd-0e07-43e2-af59-746e03181b28 xfs
/dev/sda2 988CA8A28CA87C7E ntfs
/dev/sda3 Oz6ERC-56W2-Xdf7-3aUD-B9GP-VZPP-ytBAva LVM2_member
/dev/sda5 78FCDB66FCDB1D66 ntfs New Volume

========================= "ls -R /dev/mapper/" output: =========================

/dev/mapper:
cl-home
cl-root
cl-swap
control

================================ Mount points: =================================

Device Mount_Point Type Options

/dev/mapper/cl-home /home xfs (rw,relatime,seclabel,attr2,inode64,noquota)
/dev/mapper/cl-root / xfs (rw,relatime,seclabel,attr2,inode64,noquota)
/dev/sda1 /boot xfs (rw,relatime,seclabel,attr2,inode64,noquota)


============================= sda1/grub2/grub.cfg: =============================

--------------------------------------------------------------------------------
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
set pager=1

if [ -s $prefix/grubenv ]; then
load_env
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="${saved_entry}"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
else
menuentry_id_option=""
fi

export menuentry_id_option

if [ "${prev_saved_entry}" ]; then
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi

function savedefault {
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
}

function load_video {
if [ x$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
}

terminal_output console
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=5
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/00_tuned ###
set tuned_params=""
### END /etc/grub.d/00_tuned ###

### BEGIN /etc/grub.d/01_users ###
if [ -f ${prefix}/user.cfg ]; then
source ${prefix}/user.cfg
if [ -n "${GRUB2_PASSWORD}" ]; then
set superusers="root"
export superusers
password_pbkdf2 root ${GRUB2_PASSWORD}
fi
fi
### END /etc/grub.d/01_users ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'CentOS Linux (3.10.0-514.6.1.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-514.6.1.el7.x86_64-advanced-360f5e2c-f0a9-474d-ba69-7a0ab297e59e' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$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 --hint='hd0,msdos1' f1ed9afd-0e07-43e2-af59-746e03181b28
else
search --no-floppy --fs-uuid --set=root f1ed9afd-0e07-43e2-af59-746e03181b28
fi
linux16 /vmlinuz-3.10.0-514.6.1.el7.x86_64 root=/dev/mapper/cl-root ro crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap rhgb quiet
initrd16 /initramfs-3.10.0-514.6.1.el7.x86_64.img
}
menuentry 'CentOS Linux (3.10.0-514.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-514.el7.x86_64-advanced-360f5e2c-f0a9-474d-ba69-7a0ab297e59e' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$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 --hint='hd0,msdos1' f1ed9afd-0e07-43e2-af59-746e03181b28
else
search --no-floppy --fs-uuid --set=root f1ed9afd-0e07-43e2-af59-746e03181b28
fi
linux16 /vmlinuz-3.10.0-514.el7.x86_64 root=/dev/mapper/cl-root ro crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap rhgb quiet
initrd16 /initramfs-3.10.0-514.el7.x86_64.img
}
menuentry 'CentOS Linux (0-rescue-f1baebdcc1d74b59993924b6988571f1) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-f1baebdcc1d74b59993924b6988571f1-advanced-360f5e2c-f0a9-474d-ba69-7a0ab297e59e' {
load_video
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$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 --hint='hd0,msdos1' f1ed9afd-0e07-43e2-af59-746e03181b28
else
search --no-floppy --fs-uuid --set=root f1ed9afd-0e07-43e2-af59-746e03181b28
fi
linux16 /vmlinuz-0-rescue-f1baebdcc1d74b59993924b6988571f1 root=/dev/mapper/cl-root ro crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap rhgb quiet
initrd16 /initramfs-0-rescue-f1baebdcc1d74b59993924b6988571f1.img
}
if [ "x$default" = 'CentOS Linux (3.10.0-514.6.1.el7.x86_64) 7 (Core)' ]; then default='Advanced options for CentOS Linux>CentOS Linux (3.10.0-514.6.1.el7.x86_64) 7 (Core)'; fi;
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_ppc_terminfo ###
### END /etc/grub.d/20_ppc_terminfo ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
menuentry "Windows 7" {
set root='(hd0,msdos2)'
chainloader +1
}
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f ${config_directory}/custom.cfg ]; then
source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then
source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
--------------------------------------------------------------------------------

=================== sda1: Location of files loaded by Grub: ====================

GiB - GB File Fragment(s)


======================== Unknown MBRs/Boot Sectors/etc: ========================

Unknown BootLoader on sda4

00000000 92 29 02 f2 6e f9 5e 21 58 cf c9 f7 5e 23 81 71 |.)..n.^!X...^#.q|
00000010 f6 b9 36 d8 d3 25 93 49 fa 34 54 89 85 3f 89 0d |..6..%.I.4T..?..|
00000020 fc 68 ab 1c c1 58 f9 66 65 8c 72 db 93 13 71 60 |.h...X.fe.r...q`|
00000030 f9 ea 67 b5 6d ae bc cf 9d de b2 ae 34 76 d4 2d |..g.m.......4v.-|
00000040 ce 1b ff 0d 20 70 46 c3 88 57 79 96 19 8a 39 c1 |.... pF..Wy...9.|
00000050 b7 52 c6 db f8 1a 11 0d 18 67 f1 82 3f c8 b7 9e |.R.......g..?...|
00000060 88 ac 61 6b 7a 91 c4 a5 2b 6d 38 0d bb 6f 41 26 |..akz...+m8..oA&|
00000070 16 84 9e 1c 6c c1 23 6b 12 e5 88 3e 2c bc cc 92 |....l.#k...>,...|
00000080 86 3e 4d d5 8d 6c 90 8c 59 56 92 4c 21 09 27 6e |.>M..l..YV.L!.'n|
00000090 d9 69 4e f1 8e bb 2f 9e 29 f0 e9 98 3b 64 29 87 |.iN.../.)...;d).|
000000a0 3d 85 a8 ce e9 8a c2 27 41 73 3d 5a f7 37 a9 ee |=......'As=Z.7..|
000000b0 31 10 3a 17 b2 6a d4 f6 41 55 6a 74 b0 77 cc ba |1.:..j..AUjt.w..|
000000c0 1c ea a9 73 c1 05 a2 56 cd 7b 83 70 ef 17 00 6a |...s...V.{.p...j|
000000d0 04 a4 96 8c 6c 9f b5 24 b3 cc 0b c8 28 3f a2 b9 |....l..$....(?..|
000000e0 61 e0 b4 58 63 a4 7b 3b 33 96 04 1b be c0 0d ae |a..Xc.{;3.......|
000000f0 12 eb 6f b1 4b b3 d8 14 6a 34 6a 16 9e c1 9d 2b |..o.K...j4j....+|
00000100 f7 41 c6 cc e4 d4 44 97 6f b5 89 07 55 c4 68 0f |.A....D.o...U.h.|
00000110 ea ea ee 8e e4 d2 e9 be 13 47 23 7f 30 31 22 de |.........G#.01".|
00000120 f7 ab 2c d5 e5 60 88 1c 65 eb 82 2b b8 fb 0b 64 |..,..`..e..+...d|
00000130 26 17 84 47 b4 2f 9a 3c 36 a7 0b 7a 70 d2 b5 e5 |&..G./.<6..zp...|
00000140 1e 7e 69 d1 35 87 88 a4 a9 2e 03 dd d2 f9 fc d3 |.~i.5...........|
00000150 9d b4 8c ad 14 ca 24 f7 0f fb 8f c2 4f 24 d4 9f |......$.....O$..|
00000160 77 3c 83 b7 72 58 da 4e f0 24 71 ef 04 c0 f6 42 |w<..rX.N.$q....B|
00000170 a3 eb 80 60 05 23 e2 1b 0f d3 a2 82 06 4a a1 44 |...`.#.......J.D|
00000180 08 a5 de 5b 4b bd c8 8c c6 97 b9 fa 3e 68 dc 4c |...[K.......>h.L|
00000190 93 a5 89 c9 2a 5d 17 24 18 9c 3d 8d 6d 34 f2 02 |....*].$..=.m4..|
000001a0 52 0b b3 32 04 98 dd b1 c6 2b c4 56 42 ee 07 31 |R..2.....+.VB..1|
000001b0 2e 0e 88 06 03 f6 c2 94 5d 6a d3 d7 e1 8d 00 fe |........]j......|
000001c0 ff ff 07 fe ff ff 00 18 00 01 00 c8 42 0b 00 00 |............B...|
000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200

Unknown BootLoader on cl-root'


Unknown BootLoader on cl-home'


Unknown BootLoader on cl-swap'



=============================== StdErr Messages: ===============================

cat: /tmp/BootInfo-0nAnSLez/Tmp_Log: No such file or directory
Failed to find logical volume "cl/root'"
Failed to find logical volume "cl/root'"
Failed to find logical volume "cl/root'"
hexdump: /dev/mapper/cl-root': No such file or directory
hexdump: stdin: Bad file descriptor
hexdump: /dev/mapper/cl-root': No such file or directory
hexdump: all input file arguments failed
Failed to find logical volume "cl/home'"
Failed to find logical volume "cl/home'"
Failed to find logical volume "cl/home'"
hexdump: /dev/mapper/cl-home': No such file or directory
hexdump: stdin: Bad file descriptor
hexdump: /dev/mapper/cl-home': No such file or directory
hexdump: all input file arguments failed
Failed to find logical volume "cl/swap'"
Failed to find logical volume "cl/swap'"
Failed to find logical volume "cl/swap'"
hexdump: /dev/mapper/cl-swap': No such file or directory
hexdump: stdin: Bad file descriptor
hexdump: /dev/mapper/cl-swap': No such file or directory
hexdump: all input file arguments failed
mdadm: No arrays found in config file or automatically

 

[Papaya]

You should seek advice from a Linux forum.

I do not know anything about the Linux operating system.

1. Windows 7 has boot partition. I do not have it. (Accidental deleted or didn't had, i am not sure)

Windows operating system, when the hard drive has a Master Boot Record (MBR) partition style:

If the System Reserved partition exists
- System Reserved partition (System, Active, Primary Partition)
- Windows OS partition (Boot, Page File, Crash Dump, Primary Partition)

If the System Reserved partition does not exist
- Windows OS partition (System, Boot, Page File, Active, Crash Dump, Primary Partition)

This naming convention is confusing. The "System" partition on a Windows computer is where the files needed to "boot" the computer are located. It is normally the first partition on the first hard drive enumerated by the computer's BIOS. The "Boot" partition of a Windows computer can be located on any other hard drive and contains the files for the Windows operating system.

SOURCE: Post #24 in this thread: Solved How do I restore w10 bootloader? dual boot with ubuntu on separate hdd - Page 3 - Windows 10 Forums

 

[torchwood]

couple comments.
C7 obviously overwrote your previous grub loader setting.

Got an image of both.

I would suggest you do a clean install
BUT
convert your partitoning to gpt, not limited to 4
Convert MBR Disk to GPT Disk

note W7 hates not being the primary OS, gives all sorts of problems.

Roy

 

[Megahertz07]

I use Win 7 and Lubuntu, so I can see and understand most of what you posted.

You said that you upgraded to CenOS 7 and your problems began.

What you didn't described is the problems you're having.

Are you having problems with CentOS or Win 7?

 

[os7tensed]

Problems I am facing is:

Through Centos grub2-config i was able to add Windows to Boot options.

When i opt for Windows 7 from boot options, it tells me BOOTMGR is missing.

This tells me that :

1. There is no bootmanager installed in hd0,msdos2 partition.

My question is:

2. Whether i can install a bootmanager in hd0/msdos2 partition? If yes, plz guide me to the process.
3. If 2 is not an option, how can i reuse /boot partition of xfs type to manage Windows boot files too.?


Hope problem exists somewhere between 2 and 3. I have tried Windows recovery disk and bootrec /mbr /fixboot options. They end up corrupting the linux boot partition.

So there should be a way to write windows boot files to /boot partition, if they cannot be written to hdo/msdos2 partition.

Thanks is advance again for all your time ...

Cheers!

Kapil

 

[Megahertz07]

I'm supposing that your BIOS is Legacy and your Disk is Legacy - MBR.
Normally on a legacy disk with win 7 you only have 2 partitions: MSR (RAW-120M) and C: (NTFS). In this situation, during boot, BIOS takes to MBR that takes to boot manager on C: (C:\Boot or C:\windows\Boot) where it is the boot loader.
OEM systems can have a System partition. This partition has the boot loader and programs to do maintenance and factory recover. It seems that you deleted this System partition and that is why it can't find the boot loader.
Try to copy C:\Boot or C:\windows\Boot from another computer to your windows partition and do a boot repair.

Did you do and have the Factory Restore Disks?

 

[os7tensed]

Thanks for your reply!

Here is the output of fdisk-lu

Device Boot Start End Blocks Id System
/dev/sda1 * 209717248 211814399 1048576 83 Linux
/dev/sda2 206848 209717247 104755200 7 HPFS/NTFS/exFAT
/dev/sda3 211814400 419432447 103809024 8e Linux LVM
/dev/sda4 419432448 625141759 102854656 5 Extended
/dev/sda5 436215808 625141759 94462976 7 HPFS/NTFS/exFAT


And there is a boot folder on my NTFS partition which is /dev/sda2 i.e. C:\windows\boot. There is a bootmgr file in that folder too.


Now from Linux created grub partition i.e. /dev/sda1 how can i link to this folder. Is there a way to tell grub2 where to find boot files for windows.

I think I should research for the same. If you guys have any pointers would be grateful.

Thanks MegaH for your time .....

Deeply appreciated....

 

[Megahertz07]

Try to rebuilt the grub configuration file
sudo update-grub

If it fails, with a win 7 installation disk, do a boot repair.
If you succeed you wont be able to boot CentOS.
Then load a option to windows boot loader with Easy BCD - EasyBCD - NeoSmart Technologies

 

[os7tensed]

Dear Mega,

Tried bootrepair using bootrec /MBR /FIXBOOT options. It actually corrupts the grub boot and grub options vanishes post this.

Update-grub is i think an ubuntu option, as it is not working in centos.

I think my problem would get fixed by manually configuring the settings.

I think my solution lies on the fact whether windows and centos boots can co-exist in xfs partition on my machine. Or else i need to re-create that partition so that both co-exist. By that can i rewrite my /dev/sda1 so that i can install both grub2 and windows boot files at one place.

I am not sure... so think will have to wait and research more.

 

[os7tensed]

Few Validation required, would appreciate if someone can reply:
1. Windows 7 installation : There would be 2 partitions in the system. Boot and Main. Is this correct?
- Because i do not have a boot partition.

2. Win 7 Recovery disk doesn't recognize a installed Win 7 (/dev/sda2). When does this happen? When boot partition is missing?

If answer is yes, i need to create one using win 7 recovery disk. Please share a link using which i can do that.

Thanks in advance.

 

[Megahertz07]

The default partitions on Windows depends if you have a Legacy - MBR or a UEFI-GPT system.

On a Legacy - MBR you will have a MSR -120M - RAW partition and a big NTFS where OS is installed + Linux partitions.
On a Legacy - MBR, on boot, BIOS takes to the MBR on the disk that will point to a master boot loader. This boot loader can have an option to take to another boot loader.
In your case, the boot sequence can be:
- BIOS - MBR - Linux boot loader (Grub) - options = Centos or Win boot loader- Windows
- BIOS - MBR - Win boot loader - Options = Windows or Linux boot loader (Grub) - Centos

On a UEFI - GPT you will have a UEFI 100M Fat32, MSR -120M - RAW partition and a big NTFS where OS is installed + Linux partitions.
On a UEFI - GPT, BIOS takes to the UEFI partition where can be many boot loaders. You don't have a master boot loader (Grub or win), you have both. Once you choose with one you want to boot from, it takes to the partition where the OS is.

As Grub (the master boot loader) isn't loading an option to take the sequence to windows boot loader, I suggest you to boot from a Win installation disk and do a boot repair. It will change the MBR to point to windows OS. Then, under Windows, with Easy BCD you can add an option to boot Centos.

 

[os7tensed]

Thanks Mega,

Your valuable inputs kept me going and i was able to solve it eventually.

Background:
- Had 2 NTFS partition (1 System and 1 Data)
- 1 linux boot partition
- and 1 LVM

Now Path i took was
1. Decided to create Win 7 boot partition but i already had 4 partition.
2. I deleted Data NTFS partition.
3. Created 100MB Win7 Boot Partition.
4. Used bcdboot C:\Windows /s D: where D was newly created WIN7 boot partition. which became /dev/hda1 in my disk.
5. Added /dev/hda1 as menuentry in grub.d/40_custom file
6. re-run grub2-mkconfig again.
7. This time grub identified Windows boot loader, and there i was back again.
8. Left over space due to deletion of NTFS partition was added to LVM via linux. That space was then used to extend Unix partitions in LVM.

(Off course i did all this using Win 7 Recovery Disk. You will need to browse through different drives i.e. X: to find what is loaded where. Diskpart and its commands will help you in identifying drive letters)

Thanks to all of you, I was able to learn and decide just by reading so many suggestions in the forum. It was very difficult for me to take decisions, as i had lost my centos couple of times while trying out.

Cheers!

 

[Schrade]

Papaya - why run OP off to another forum?

I'm sure there's someone I here, who sees and I can see the entire problem in the thread title, and fixed it many times.

Solution posted in the am here OP (did you mean MBR ??? )


edit: In fact, I don't need to get to the other pc for this one.
Insert your W7 CD / DVD, 'option repair your computer' - you need to get to a CLI (command prompt), then enter the repair command for your error (google search will give you the command).

THEN, you'll have to reinstall the GRUBLoader to correct partition because W7 repair will jam Grub.

You familiar with GRUB reinstall? And do you know the GRUB version on your Linux CD?