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Asus Prime B365M-A, NVME and Secure Boot questions

jonwil
Level 7
I have an Asus Prime B365M-A with a Core i5-9400F.
I have a Crucial CT500P1SSD8 NVME SSD as my boot drive in the lower m.2 slot below the PCI-E x16 slot and nothing in the upper m.2 slot above the PCI-E x16 slot.

I want to enable secure boot. I have been told that in order to enable secure boot I need to disable CSM in the bios but when I do that, my NVME disk is totally invisible to the system and the system wont boot anymore.

Questions:
1.Do I need to reinstall Windows to get secure boot working? (and if so, what do I do for that? Do I just need to disable CSM in the bios and then boot from a Windows 10 or 11 install drive and install Windows or is there more to it?
2.Do I need to have my boot NVME SSD in the upper NVME slot (the one above the PCI-E x16 slot and closer to the CPU) in order for the disk to be recognized and booted from with CSM off and secure boot on?
and 3.If I need to have the boot NVME SSD in the upper slot for it to boot with CSM off and secure boot on, can I have a second SSD in the lower m.2 slot and use it for data or does the lower m.2 slot not work at all with CSM off and secure boot on?

I have read the manual and all the information online (and done various Google searches) but I can't find any information about just how the 2 m.2 slots on my board work when CSM is off, which slot I need mty boot drive in and which slots I can use a data drive in.

Hopefully someone here knows enough about my board to know what steps I need to take in order to have secure boot working (and whether I can have both m.2 slots populated with NVME drives in this configuration)
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2 REPLIES 2

Gus_Ghanem
Level 7
I don't have an answer, but is your boot drive using GUID Partition Table (GPT) (it should be using GPT not MBR)... Is your BIOS UEFI?

How do I figure out what settings I have?