Arch Linux

ultimatr

Member

Registered: 2021-03-17

Posts: 19

[SOLVED] GRUB "cannot find ntldr" when trying to boot into Windows 10

Greetings,

I'm trying to configure my /etc/grub.d/40_custom to boot my windows 10 partition which is on /dev/sdb1

My 40_custom currently

#!/bin/sh
exec tail -n +3 $0
#
#
#

menuentry "Windows 10" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    insmod search_fs_uuid
    insmod ntldr
    search --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 --fs-uuid 1A9ED2D49ED2A811
    ntldr /bootmgr
}

But when I try to boot into my Windows 10 entry:

error: can't find command 'ntldr'

How do I fix this?

Last edited by ultimatr (2021-03-19 16:52:05)

ponyrider

Member

Registered: 2014-11-18

Posts: 112

Re: [SOLVED] GRUB "cannot find ntldr" when trying to boot into Windows 10

grub can detect other operating systems

https://wiki.archlinux.org/index.php/GR … ng_systems

you shoudn't need to create a custom config

ultimatr

Member

Registered: 2021-03-17

Posts: 19

Re: [SOLVED] GRUB "cannot find ntldr" when trying to boot into Windows 10

grub can detect other operating systems

https://wiki.archlinux.org/index.php/GR … ng_systems

you shoudn't need to create a custom config

Good idea.

I went ahead and installed os-prober and NTFS-3G in order to mount my bootable windows partition.
I removed my old configuration in 40_custom as well.
Reran grub-mkconfig and saw a lot more shit print out.

This time when I reboot, Windows 10 is an option.
When selected, the same exact error occurs...

error: can't find command 'ntldr''.
Press any key to continue...

ponyrider

Member

Registered: 2014-11-18

Posts: 112

Re: [SOLVED] GRUB "cannot find ntldr" when trying to boot into Windows 10

Seems like you are trying to use BIOS mode rather than UEFI mode

You have obviously screwed up somewhere. Please read the archwiki and post back if you still have any errors

ultimatr

Member

Registered: 2021-03-17

Posts: 19

Re: [SOLVED] GRUB "cannot find ntldr" when trying to boot into Windows 10

Seems like you are trying to use BIOS mode rather than UEFI mode

You have obviously screwed up somewhere. Please read the archwiki and post back if you still have any errors

ls /sys/firmware/efi/efivars

efivars runs fine, so I believe I am in UEFI mode.

I tried rerunning grub-install just in case

grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=GRUB

and I get an error

grub-install: error: efibootmgr failed to register the boot entry: Input/output error.

I don't know at this point. I guess I'll keep rereading through the grub wiki until I figure it out

ultimatr

Member

Registered: 2021-03-17

Posts: 19

Re: [SOLVED] GRUB "cannot find ntldr" when trying to boot into Windows 10

Fixed problem by deleting windows 10.

Bye bye windows. Hello arch

smallberries.john

Member

Registered: 2020-11-19

Posts: 5

Re: [SOLVED] GRUB "cannot find ntldr" when trying to boot into Windows 10

Windows 10 doesn't use NTLDR.