Installed Debian Linux to Dualboot with Windows 10, but can't boot to Debian

How to fix: After Installing Debian for dualbooting with Windows 10, just boots straight to WIN10 without a choice

Let's say you have installed Debian with Windows 10, in your UEFI system, you have all the right kernel parameters set and UEFI configs and all the partitions are all set and mounted right, windows 10 was installed before you installed Linux and you got /boot/efi at fat32/vfat FS, but your comp just boots straight to Windows 10 without a choice to boot to Debian, the reason is Windows will usually try and make its bootloader default again which means Debian isn't an option, well the easy fix as long as you got everything right on the basic install would be:

1.) Boot up Windows 10

2.) Then start a terminal console (command prompt), but run as administrator

3.) Issue this command at the console:

bcdedit /set {bootmgr} path \EFI\debian\grubx64.efi

4.) Reboot, and it should give you a choice to boot to Debian Linux or Windows 10 now, if not look to changing the boot order of operating systems installed in your computer in your computer firmware, and change it to Debian as mentioned in NOTES below.

- You can reuse the EFI partition that windows 10 uses, just mount that as /boot/efi with Linux, its recommended that there be only one EFI partition per disk, so if you have 2 disks and you install windows and linux in each disk you can either reuse the efi partition that windows 10 has but make sure its atleast 300MB or bigger, you can resize the partition before installing, but dont delete and format the existing EFI windows 10 is using as it already contains necessary files Windows 10 needs or you can and this is recommended just make another efi partition on the disk linux will be installed in.
- There's also the option to change the boot order of OS'es in the BIOS/UEFI firmware of your computer/laptop, however there are many versions and kinds of firmware and each firmware can look somewhat different, so its kinda tough to give a step by step one size fixes all procedure here about that but the option to choose the order should be located in the BOOT category, all you have to do then is make sure you set Debian as the primary OS at boot, save then exit and restart.
- You could also try GrubEFIReinstall
- For Ubuntu you can use:

bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi 

in place of the debian command above.


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