Gygabyte Z270X-UD5 and M.2 device

[samedivv]

Recently (1 month ago) I buyed this motherboard and a M.2 Samsung EVO 960 device, and other components to mount a new PC. When I first mounted all the PC I installed Windows 10 on M.2 device without any problem, installed all the drivers, updated the BIOS to F2 version, and the PC worked like a charm.
A few days ago, I switched on the PC and it tried to load an existing OS in another hard disk. I restarted and entered BIOS, and I didn't see the M.2 device under NVMe setting, it showed "No NVMe device found". I restarted several times but there was no lucky. After that, I switched off the AC main power and switched on again, entered the BIOS, and this time M.2 device was listed on it. So I changed boot priority and launched the OS and everything went perfect. Also I updated BIOS to the recently F3 version, restarted and no problem at all, during all day.
Ok, next day, same situation, I switched on the PC and there was no device, this time I switched off AC main power and loaded optimized defaults in BIOS, after that all went ok.
Since then, all days I must do those steps to make the BIOS recognize the M.2 device. As additional information, SATA0 port is free to be occuped by the M.2 device.
My question is if I must do a RMA, or is something that can be fixed.

[shadowsports]

This is not a defect.

You should not rely on your BIOS to take the place of a Boot Manager which is what you should be using for a dual or multi-boot system.

Incorrect BIOS settings, or installing the host OS incorrectly can cause NVMe detection failures.

Other suggestion would be to use a VM for the guest OS.

[samedivv]

Maybe you missunderstood me. I only have one working OS in my system, the one that is installed in M.2 device. There are other not working OS in another HDD that is booting (and failing, of course) when the BIOS doens't detect the M.2 device.
My issue is only related to the random detection of the M.2 device, not booting at all.

[samedivv]

Sincerely I give up, you don't want to understand and with this answers you want make me a dumb or something.

First, I'm IT engineer, the OS doesn't take place in a BIOS device detection. Maybe I didn't install any OS but the BIOS must detect all the devices, and, if an OS is incorrectly installed the BIOS will boot up and launch the first device on the boot sequence, then will fail to launch the OS, but at this place BIOS will have done its job flawlessly.

Second, I have worked with this mobo for a month without any issue, but one day, without any message, without any change in the BIOS setup, the mobo doesn't detect M.2 device.

Finally, everyday, after 2-8 reboots the BIOS detect the device, launch the OS, work for all day without issues (bad installed OS, ok  ) switch off the PC at night, and in the next morning I have again the same detection issues.

Sorry for the angry answer, but I don't like to be cheated.

[shadowsports]

Hey man.  I was working. 
 
I understand what you are saying now.  There are no wrong answers and we are all here to help one another.  I know how frustrating a problem like this can be.  Been through it myself many times.  What I'd like to say is roll back your BIOS to the one that worked.  That seems to be what caused the behavior.  With that however comes another issue.  The MAC address on your primary NIC might change. 

You may notice I am 2 BIOS revs behind what is currently available for my board.  That's because I have a working system that is stable.  Most BIOS updates are safe.  They often address issues, improve function and can also add support for new hardware.  While tempting, having the latest isn't always a good idea.  Depending on your hardware and how you use your system, upgrading can also introduce problems or undesirable behavior. 

When disk detection failures occur, I usually look at the drive first, then BIOS settings.  Fully loaded systems with multiple disks connected to various interfaces can have detection issues caused by many things.

How the drive was prepped
BIOS settings - Fast Boot / Ultra Fast Boot options in BIOS or App Center App
Combination of other connected hardware (timing issues)
Aggressive Over Clocking settings, etc
Using your BIOS boot order menu in place of a boot manager when multiple OS's exist (not in your case, I know)

Since you had a working system, I'd consider downgrading my BIOS.   

[samedivv]

Thank you for the answer. This is better now.

I updated the BIOS because I had detection issues with prior version, if I hadn't I never would have updated the BIOS, if something works don't touch it.

The drive seems to work perfect because I had no BSOD, not writing/reading failures and the OS works like a charm, but without issues is hard to know if really does.

BIOS settings were setup at first time with no issues in a month, and in that time I never changed it, neither update it. Also as it was the first month with the computer I didn't make overcloking changes, all frequencies and voltages were the same as stock.
Also, I've checked disconnecting all the other drives and the situation is the same.

I think is something related to power inside the motherboard, because only detects the device if I have switched off AC power before switching on the PC, no matter how many times I reboot it.

Finally, I can't downgrade BIOS because the last update prohibits it. (I tried to and is true :S)

[shadowsports]

It can be done.  Start here.

https://forum.giga-byte.co.uk/index.php?topic=18449.0

or

https://forum.giga-byte.co.uk/index.php?topic=17957.0

Make sure you read the threads in their entirety.