Can't change the disk boot priority

[Flamewalk]

Hello.

I just swapped the Intel Optane for an M.2 SSD and cloned the system into it.

Problem: can't change the disc boot priority to start Windows from an SSD and not the default HDD

Here's what I did:

1. Used Intel Rapid Storage Tech program to disable the Optane memory.

2. Shut down and remove the Optane card from the M.2 slot and install the Kingston A2000 NVMe drive (500 Gb).

3. Then, used Acronis to clone the operating system from the 1Tb Hard drive to the 500 Gb  SSD NVMe drive in the m.2 slot.

4. Formatted the main partition of the HDD to remove Windows (I took this step later in attempt to prevent the old OS from loading).

Here's what I have:

every time I start the laptop, it tries to boot from the HDD, finds out there's no OS and starts the Windows recovery tool

I can force the cloned Windows from the SSD to load by pressing ESC -> F9 -> selecting OS Boot Manager (UEFI) on the SSD. In this case the cloned Windows copy starts and works normally.

I tried changing the disc priority order in BIOS by going to System Config -> Boot Options -> OS Boot Manager. I can move SSD and HDD in the OS Boot Manager menu up and down by pressing F5/F6, but every time I check it again, the HDD is always first.  Anyway, meddling with any boot options in BIOS doesn't seem to make any difference, the HDD always stays the first boot device and always tries to load non-existing Windows.

I also tried turning off Secure Boot and turning on Legacy Support - also, no effect.

I would be very grateful if you give me an idea how to make the M.2 SSD a default boot device without the necessity to remove the HDD.

[Flamewalk]

Ok, I finally figured it out myself.

Turns out that the solution was really obvious (yeah, me stupid).

When you set the disk boot priority in the OS Boot Manager submenu by pressing F5/F6, then you need to confirm the change by pressing F10, otherwise changes are discarded.