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Dual boot Win 10 & Kubuntu 20.04.3 - default bootloader stays Windows

cn flag

I am trying to get GRUB to be the default bootloader at boot time. I have a Samsung 500 GB SSD and a Crucial m.2 500 GB drive. Windows 10 is on the Samsung SSD. I have installed Kubuntu on the m.2 drive with an EFI partition created in the first 700 MB, and it is designated as the boot sector during installation. The remainder of the drive is allocated to root, swap, and home.

I can tap my F9 key during startup to get the boot order menu, select my m.2 drive and get into Linux, but otherwise the Windows bootloader is the default and will automatically boot into Windows. I cannot get GRUB show without tapping F9. In the BIOS, the boot order does not even show the second drive as a selection option.

I have tried multiple settings: enabling/disabling Legacy Mode, enabling/disabling Secure Boot, disabling Fast Boot in Windows., and various suggestions I have seen on the net for terminal commands.

I assume the Windows EFI file on the SSD is being read first, but I haven't read anything about deleting that partition.

Any suggestions?

ChanganAuto avatar
us flag
There's no need for a second ESP and in some cases it cause problems. In UEFI mode the boot process boot entries in the ESP (again, only ONE is better), not drives. So, before anything else, you need to understand how UEFI works.
Robert Hoffman avatar
cn flag
I actually failed to mention that I had also tried multiple times to install with only one ESP and had directed bootloader to install on the first disk (Windows EFI). No difference.
ChanganAuto avatar
us flag
Either way you need to open UEFI > Boot and change the boot order to "Ubuntu". Whether it sticks or not remains to be confirmed. Some HP models always boot Windows no matter what users do. That being the case F9 must be used.
Robert Hoffman avatar
cn flag
Thanks for the suggestions. However, UEFI on my HP laptop does not give me the option to change to change to Ubuntu. I can change my boot order from usb cd, usb flash drive, network or the listed ssd drive that has Windows - no other choice for Ubuntu or for the installed drive. Even when I put Kubuntu in partitions on the same drive as Windows it did not change my choices. I guess I am just stuck with F9 to get into Linux.
ChanganAuto avatar
us flag
That shouldn't happen if the OSes are actually installed in UEFI mode. By the looks of it you have Legacy/CSM enabled and the OSes installed in Legacy mode.
oldfred avatar
cn flag
If all installs are UEFI, with HP you have to change boot order in UEFI settings (not UEFI boot menu). HP for whatever reason does not work with efibootmgr which grub also uses to make Ubuntu/grub first in boot order. You may also need to update UEFI firmware from HP. But be sure all installs are UEFI. You should only have one ESP per drive/device, but can have one per drive if multiple drives. Its just Ubuntu's Ubiquity installer will only use first one found, usually the Windows one.
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