Booting windows (grub and legacy)

Dear Supporters,

now I come up with a problem here, and I can document it like this:

I have a KDE MANJARO fresh install. Manjaro OS and Windows 10.:
sda 8:0 0 278.9G 0 disk
├─sda1 8:1 0 512M 0 part /boot
├─sda2 8:2 0 40.5G 0 part
├─sda3 8:3 0 180G 0 part /mnt/share
├─sda4 8:4 0 1K 0 part
├─sda5 8:5 0 10G 0 part
├─sda6 8:6 0 4G 0 part [SWAP]
└─sda7 8:7 0 43.9G 0 part /

bootflag is with sda1

When I opt for Manjaro in the grub boot menu (legacy), I can boot.
When I opt for windows, it says “this is not a bootable disk. Please insert a bootable dism, floppy…”

Why would that be? Can the boot flag go to the windows partition?


PS: I toggled the boot flag already as I can see:

[siserhost siser]# fdisk /dev/sda --list
Festplatte /dev/sda: 278.88 GiB, 299439751168 Bytes, 584843264 Sektoren
Festplattenmodell: PERC H310       
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes
Festplattenbezeichnungstyp: dos
Festplattenbezeichner: 0xba6160c1

Gerät      Boot    Anfang      Ende  Sektoren Größe Kn Typ
/dev/sda1            2048   1050623   1048576  512M 83 Linux
/dev/sda2  *      1050624  85985279  84934656 40.5G  7 HPFS/NTFS/exFAT
/dev/sda3        85985280 463472639 377487360  180G  c W95 FAT32 (LBA)
/dev/sda4       463472640 584843263 121370624 57.9G  5 Erweiterte
/dev/sda5       463474688 484446207  20971520   10G  7 HPFS/NTFS/exFAT
/dev/sda6       484448256 492836863   8388608    4G 82 Linux Swap / Solaris
/dev/sda7       492838912 584843263  92004352 43.9G 83 Linux

sda3 is supposed to be share. Win 10 on sda2. manjaros boot on sda1.
grub is the automated install by the manjaro installer.
I had a custum entry before, but without success.

siserhost siser]# cat /etc/grub.d/40_custom  
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type th
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.

Hello @MrBo :wink:

When installing by bios-boot, then grub overwrites the MBR since only one bootloader can exists.

If you would like to boot windows while have having linux installed, then grub have to do that.

To boot ONLY windows again, you will need to overwrite the MBR with windows and boot it.

Good so far.

That could have 2 problems:

  1. Wrong partition.
  2. Bootloader of Windows is corrupted/deleted.

Well as mentioned yesterday in the other thread, I found a solution.
For me, the “ntldr (hd0,msdos3)/bootmgr” part made difference. Without the (hd0 …) specification it didnt work.

HOWEVER, YES, I must have deleted some part of Windows boot application, since it was in the MBR (I guess, by standard). I overwrote it.
Is that the way to go, and replace it with grub?


BOOTLOADER Install (legacy) in support