修改

Change grub2 default startup item in Fedora

by

Confirm our OS is in BIOS or EFI,

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# in BIOS system
GRUB_CFG=/boot/grub2/grub.cfg
# in EFI system
GRUB_CFG=/boot/efi/EFI/fedora/grub.cfg

Then lookup the booting item id we want to set as default.

If we only want to switch default between Linux kernels,

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grubby --info ALL

Else if we want to change default booting item to Windows,

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cat $GRUB_CFG | grep Windows

Read the output, we will find the item, e.g. corresponding to the name, the id is "e528434f2b3e4d7c97d97aa4aabb976e-5.16.7", write it in /etc/default/grub

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#GRUB_DEFAULT=saved
GRUB_DEFAULT=e528434f2b3e4d7c97d97aa4aabb976e-5.16.7

Finally update grub,

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grub2-mkconfig -o $GRUB_CFG
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Reboot to see the change.

And in Ubuntu, how to make grub2 remember last choice?

sudo vi /etc/default/grub
	GRUB_DEFAULT=saved
	GRUB_SAVEDEFAULT=true
sudo update-grub

refer to:
https://docs.fedoraproject.org/en-US/fedora/f35/system-administrators-guide/kernel-module-driver-configuration/Working_with_the_GRUB_2_Boot_Loader/

Fedora 21 改变启动顺序以及grub2 配置技巧


https://askubuntu.com/questions/148662/how-to-get-grub2-to-remember-last-choice