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How to boot one windows os from ubuntu grub menu

jm flag

How can i boot one windows from ( i have 2 windows and 1 ubuntu os in system) from grub. 2 windows but have only one windows boot manager. when i boot windows boot manager from grub it needs an extra effort each time to choose which windows os is boot. so if write a code to grub menu entry to boot specific os say 'windows 1' i can boot that os without going to windows boot manager.

i tried to boot D:\Windows\system32\winload.efi from grub bootloader. but it caused error. and most answers gives to boot windows boot manager. Then is there any to create more 1 windows boot manager for only loading one windows os on each boot manager. so i can add that 2 boot managers to grub menu entry.

i'm using a gpt partition in my ssd, ubuntu 22.04, 2 windows both are windows 10

oldfred avatar
cn flag
Windows uses BCD to dual boot. Second install of Windows adds both installs to BCD in ESP - efi system partition. Some have created a second ESP (FAT32 - boot,esp flags), temporarily, and repair installed Windows to get new BCD. Move boot, esp flags back, but os-prober does not know ESP (grub install does). So then you can create a grub entry to FAT32 partition with just the one Windows efi files.
jm flag
thanks, so can i boot 'windows 1' from grub without entering windows boot manager?
oldfred avatar
cn flag
With some work to have another Windows entry in a FAT32 partition. I believe new install not required, if you can run repair or create new UEFI boot entries. https://askubuntu.com/questions/653101/boot-repair-windows-not-listed I would only keep one FAT32 active as ESP.
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