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-=GGW=- $ol!d $n4>|e
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Joined: 12 Apr 2004
Posts: 1616
Location: USA
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 Posted: Mon Apr 06, 2020 9:48 pm Post subject: chainloader UEFI GPT grub2 windows 10 errors [SOLVED] |
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Hey all, sorry for the most likely duplicate post. I've done searching on the wiki and forums and none of the solutions seem to work for me. I can not get grub to chainload into windows uefi. I"m going to do my best to describe all scenarios attempted here.
First off: env
Gentoo is on /dev/sdb and is installed via UEFI and the partition is setup with GPT. Here is parted print of that drive
| Code: |
GNU Parted 3.2
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
Model: ATA Samsung SSD 860 (scsi)
Disk /dev/sdb: 2000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 3146kB 2097kB grub bios_grub
2 3146kB 137MB 134MB fat32 boot boot, esp
3 137MB 17.3GB 17.2GB linux-swap(v1) swap
4 17.3GB 2000GB 1983GB ext4 rootfs
(parted)
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Windows is on /dev/sda in gpt mode using UEFI
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GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
Model: ATA Samsung SSD 860 (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 556MB 555MB ntfs Basic data partition hidden, diag
2 556MB 661MB 105MB fat32 EFI system partition boot, esp
3 661MB 677MB 16.8MB Microsoft reserved partition msftres
4 677MB 1000GB 1000GB ntfs Basic data partition msftdata
(parted)
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Both these boot fine from the bios in UEFI mode. If i boot to grub however, I cannot get windows to chainload. I've tried using os-prober which results in this entry
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### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Boot Manager (on /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-efi-AAB8-4BF1' {
insmod part_gpt
insmod fat
set root='hd0,gpt2'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2 AAB8-4BF1
else
search --no-floppy --fs-uuid --set=root AAB8-4BF1
fi
chainloader /efi/Microsoft/Boot/bootmgfw.efi
}
### END /etc/grub.d/30_os-prober ###
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and that results in an errormessage
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error: no such device: AAB8-4BF1
error: file `/efi/Microsoft/Boot/bootmgfw.efi` not found.
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I've tried a manual entry
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### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
menuentry "Windows" {
insmod part_gpt
insmod chain
insmod fat
set root='hd0,gpt2'
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
### END /etc/grub.d/40_custom ###
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that yiedls the error
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error: file `/EFI/Microsoft/Boot/bootmgfw.efi` not found.
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The fat32 partition on /dev/sda2 looks as follows
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EFI
EFI/Boot
EFI/Boot/bootx64.efi
EFI/Microsoft
EFI/Microsoft/Boot
EFI/Microsoft/Boot/bootmgfw.efi
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I"m at a loss on how to get chainloading working in this setup  |
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-=GGW=- $ol!d $n4>|e
Veteran
Joined: 12 Apr 2004
Posts: 1616
Location: USA
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| Posted: Tue Apr 07, 2020 2:30 am Post subject: |
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Well, foot in mouth time :X
Posting a follow up in case anyone else runs into this and happens to stumble across this post.
I used to have a dying hard drive and a broken cdrom in this comp that would take forever during boot. Being the lazy human I am I didn't remove the sata cables but turned on fast boot in my bios. That was fine before when I had a hybrid setup. Now that everything is UEFI, grub only seeis the one drive my bios thought was needed to boot and cant see the other drives. Turning off fast boot in my bios resolved the issue and the os prober entry works like a charm.
To diagnose this I used the grub console and ls to poke around the drives and noticed that grub only saw 1 drive ever. :X |
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Installing Gentoo
