Problem booting into Windows 10 after installing Ubuntu on a different Hard Drive...?

[Supersonicwolfe]

I'm in a weird situation here. 

I took out my Windows 10 SSD and a hard drive and installed a separate hard drive into my old laptop just to try it out. I installed Ubuntu 22.04.2 LTS on to it.

Now I took out that hard drive and reinstalled the SSD and hard drive back into the laptop. But now Windows 10 won't boot in "UEFI mode with secure boot" and somehow I do still see a boot option called Ubuntu.

In addition I can only boot into Windows 10 through UEFI mode with CSM (Legacy) support. Windows Boot Manager does show up when the BIOS is in the "UEFI mode with secure boot" and "UEFI mode without secure boot" (without CSM), but the laptop does nothing when I tried to boot though that.

Windows 10 still reports its in UEFI mode even if I boot through UEFI mode with CSM (Legacy) support?

 

 

Is there anyway to fix this? I haven't tried Window's start-up repair (doesn't seem likely it will do anything since I took out the SSD when installing Ubuntu... nothing should have changed to the system).

The only other way I can think of is reflash BIOS, but I guess that also means I will have to re-intall Ubuntu down the line.

[Supersonicwolfe]

So I tried start up repair, which returned as "Windows failed to repair the problem" and then flashed the bios, and now I can get the secure boot working on in Windows.

Still don't understand why Ubuntu is listed as boot option despite the hard drive with ubuntu is not even connected in the system... or why Windows couldn't boot initally UEFI 

[LloydLynx]

On 4/20/2023 at 6:31 PM, Supersonicwolfe said:

Still don't understand why Ubuntu is listed as boot option despite the hard drive with ubuntu is not even connected in the system... or why Windows couldn't boot initally UEFI 

UEFI works different than BIOS. UEFI doesn't look for bootable drives on each boot. Boot devices in UEFI are stored as entries that are created by the OS upon installation. It's like creating a file; it sits there until you do something with it. Except that "file" is stored on your motherboard. 

[Supersonicwolfe]

On 4/23/2023 at 6:52 PM, LloydLynx said:

UEFI works different than BIOS. UEFI doesn't look for bootable drives on each boot. Boot devices in UEFI are stored as entries that are created by the OS upon installation. It's like creating a file; it sits there until you do something with it. Except that "file" is stored on your motherboard. 

I thought flashing BIOS will also wipe out that information. But even after I reflash the BIOS, the Ubuntu boot option is still there.

 

On the other hand, since after re-flashing the BIOS, windows 10 boots fine with secure boot. So I'm not going to continue worry about this... Probably something have to do with this is a Dell Laptop... Old one too (3rd gen core, basically the tail end of transition period between Legacy and UEFI bios. I remember this laptop used to have Legacy BIOS from factory.)