Re: Is it possible to dual-boot both MBR & GPT without changing BIOS settings on laptop

On 2026-02-20 20:01, Java Jive wrote:
> On 2026-02-20 18:46, Paul wrote:
>> On Fri, 2/20/2026 12:44 PM, Java Jive wrote:
>>> On 2025-11-11 13:19, Java Jive wrote:
>>>> On 2025-11-11 03:45, Paul wrote:
>>>>>
>>>>> On Mon, 11/10/2025 7:27 PM, Java Jive wrote:
>>>>>>
>>>>>> Then reboot, and it all works.
>>>>
>>>> Except, I've discovered, OSs won't hibernate, all that happens is 
>>>> that the screen locks, the PC doesn't even sleep, let alone hibernate.
>>>
>>> I wrote this some time ago, so can not be sure now what was going on 
>>> then, but my suspicion is that it was the same as I recently 
>>> discovered on one particular PC ...
>>>
>>> The PC has a single GPT disk dual-booting between Windows 11 & Ubuntu 
>>> 24.  I have two GRUB entries to boot Windows 11.  The first is a 
>>> conventional Windows Boot Manager entry in the EFI partition, the 
>>> second is similar but installed in the Windows 11 partition \EFI 
>>> folder.  If Windows 11 is booted via the first option, it hibernates, 
>>> but if it booted via the second option, it won't hibernate as 
>>> originally I described above.  I think it's something to do with 
>>> Ubuntu/GRUB not being able to access some needed data on the ntfs 
>>> partition when booting.
>>>
>>> The relevant entries in /boot/grub/grub.cfg are as follows:
>>>
>>> # Boots and hibernates
>>> menuentry 'Windows Boot Manager (on /dev/sda1)' --class windows 
>>> --class os $menuentry_id_option 'osprober-efi-E00A-0248' {
>>>          savedefault
>>>          insmod part_gpt
>>>          insmod fat
>>>          set root='hd0,gpt1'
>>>          if [ x$feature_platform_search_hint = xy ]; then
>>>              search --no-floppy --fs-uuid --set=root 
>>> --hint-bios=hd0,gpt1 --hint-efi=hd0,gpt1 --hint-baremetal=ahci0,gpt1
>>> E00A-0248
>>>          else
>>>            search --no-floppy --fs-uuid --set=root E00A-0248
>>>          fi
>>>          chainloader /efi/Microsoft/Boot/bootmgfw.efi
>>> }
>>> # Boots but does not hibernate
>>> menuentry 'Windows 11 Professional (on /dev/sda2)' --class windows 
>>> --class os $menuentry_id_option 'osprober-efi-53C598050A7F9BDA' {
>>>          savedefault
>>>          insmod part_gpt
>>>          insmod ntfs
>>>          set root='hd0,gpt2'
>>>          if [ x$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 
>>> 53C598050A7F9BDA
>>>          else
>>>            search --no-floppy --fs-uuid --set=root 53C598050A7F9BDA
>>>          fi
>>>          chainloader /EFI/Microsoft/Boot/bootmgfw.efi
>>> }
>>
>> The first entry has a short disk identifier, suggesting the ESP FAT32 
>> partition.
>>
>> The second entry has a long disk identifier, suggesting the NTFS OS 
>> partition,
>> which does not particularly have a /EFI/Microsoft/Boot/bootmgfw.efi and
>> so "something else" is happening there when it boots. While the second 
>> entry
>> might be able to find C:\boot (which third-party tools might use), it 
>> would
>> take a BCD file to point to that, at a guess.
> 
> Yes, basically I would prefer a system where everything needed to boot 
> an OS is contained within that OS' partition.  Therefore, when setting 
> up the dual-boot I ran the following command to install a secondary BCD 
> file onto the C: drive in addition to the one in the FAT32 EFI partition 
> ...
> 
> C:\Windows\System32\BCDBoot C:\Windows /s C: /f ALL
> 
> ... and, because the default option name for such installs is "Windows 
> Boot Manager", to remove the ambiguity between the additional option on 
> the C: drive and the usual one in the EFI partition, I then ran ...
> 
> BCDEDIT /set {default} DESCRIPTION "Windows 11 Professional"
> 
> ... which simply renames the additional option so that the two options 
> will appear in GRUB under two different ...

... names!

> As I have explained, the additional option does indeed boot fine, 
> seemingly entirely normally, it's only when you try to hibernate the OS 
> that it becomes apparent that something is wrong.

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