[SOLVED] M.2 SSD not recognized in Boot bios- Asus z490-A Gaming Strix

Nov 17, 2020
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I have a Sabrent Rocket Q 1TB NVMe PCIe M.2 2280 installed in the M.2_1 slot of an ASUS Z490-A Strix Gaming motherboard. When I first installed it, my computer wouldn't POST as the motherboard couldn't detect the M.2 SSD as bootable. I was able to solve this by putting a regular SATA SSD and connecting it to the motherboard which allowed me to finally POST and even install Windows on the M.2. However, after several weeks I am unable to disconnect or even set the M.2 SSD as the bootable drive, as in the BIOS only the SATA SSD is recognized as a bootable drive. Yet whenever I start my PC after the initial "press del to enter bios screen" it allows me to choose where I'd like to boot up from. Either the M.2 or the SATA SSD, which I've already set as default to the M.2 but this takes away a few seconds from the start-up time and it's still rather odd that I can't set the M.2 as the bootup drive despite the fact that my computer recognizes it and is able to boot up to it, albeit not immediately. The moment I remove the SATA SSD from the motherboard, my computer would be unable to post until I reconnect it.

I have already tried disabling the CSM, setting secure boot to another OS, cleared the boot keys, etc.

Right now I'm just glad my computer is up and running but I still find it rather odd and quite a hassle that my computer can't run without a separate SATA SSD when it has a perfectly good and running M.2 SSD inside.
 
Solution
Oh sorry. Here it is
As suspected ..
Do you see that small 100MB EFI System partition? That is bootloader partition.
Only drive containing bootloader is bootable. That is your 120GB drive.
M.2 drive doesn't have a bootloader, so it is not bootable.

Execute following commands from elevated command prompt. Regular command prompt will give error on last command.
(if you get any errors, then stop immediately)
diskpart
list disk
select disk 2
list partition
select partition x
(select 931GB partition, x=1 or x=2)​
shrink desired=500
create partition efi
format fs=fat32 quick
assign...
Welcome to the forums, newcomer!

We will need a little more information. Can you please list your full system's specs? You could try and place the SSD on the other slot and see if that works out for you. Which slots are you populating for your rams? Can you check and see which BIOS version you're on at the time of writing? If you have BIOS updates pending, take note of the instructions mentioned here with regards to Intel's MEI drivers.
 
The moment I remove the SATA SSD from the motherboard, my computer would be unable to post until I reconnect it.
Can you show screenshot from Disk Management?
(upload to imgur.com and post link)

If you installed windows, while sata ssd and nvme drive was both connected, then bootloader most likely has been placed on sata ssd. So only sata ssd is bootable and nvme drive is not.
You can fix this by creating bootloader partition on nvme drive manually.
 
Welcome to the forums, newcomer!

We will need a little more information. Can you please list your full system's specs? You could try and place the SSD on the other slot and see if that works out for you. Which slots are you populating for your rams? Can you check and see which BIOS version you're on at the time of writing? If you have BIOS updates pending, take note of the instructions mentioned here with regards to Intel's MEI drivers.


Hi full system specs are

intel core i7 10700k 3.8 ghz
ASUS ROG STRIX Z490-A Gaming Motherboard
2x Corsair Vengeance RGB Pro 8gb DDR4-3200 Mhz
Wester Digital 1.5GB TB HDD
Corsair SATA SSD 120GB
Sabrent Rocket M.2 SSD 1TB



The Ram is connected to DIMM A2 and DIMM B2


For BIOS I think it's whatever it was when it came out of the box. I'll check.
 
Hi full system specs are

intel core i7 10700k 3.8 ghz
ASUS ROG STRIX Z490-A Gaming Motherboard
2x Corsair Vengeance RGB Pro 8gb DDR4-3200 Mhz
Wester Digital 1.5GB TB HDD
Corsair SATA SSD 120GB
Sabrent Rocket M.2 SSD 1TB



The Ram is connected to DIMM A2 and DIMM B2


For BIOS I think it's whatever it was when it came out of the box. I'll check.
My bios version is 0403 x64
 
Can you show screenshot from Disk Management?
(upload to imgur.com and post link)

If you installed windows, while sata ssd and nvme drive was both connected, then bootloader most likely has been placed on sata ssd. So only sata ssd is bootable and nvme drive is not.
You can fix this by creating bootloader partition on nvme drive manually.
Hi this is the shot I got from the disk management boot drive in the BIOS

View: https://imgur.com/gallery/VUadPQA
 
Hi this is the shot I got from the disk management boot drive in the BIOS
That is not Disk Management.

It looks like this:
disk-management-windows-10-58a5d33a3df78c345b052f96.PNG
 
Oh sorry. Here it is
As suspected ..
Do you see that small 100MB EFI System partition? That is bootloader partition.
Only drive containing bootloader is bootable. That is your 120GB drive.
M.2 drive doesn't have a bootloader, so it is not bootable.

Execute following commands from elevated command prompt. Regular command prompt will give error on last command.
(if you get any errors, then stop immediately)
diskpart
list disk
select disk 2
list partition
select partition x
(select 931GB partition, x=1 or x=2)​
shrink desired=500
create partition efi
format fs=fat32 quick
assign letter=H
exit
bcdboot C:\windows /s H:
After this is done shutdown, disconnect sata SSD, change boot priority so Windows Boot Manager on M.2 drive is first in boot order and test, if your system can boot into windows.

Here's, how to open elevated command prompt:
 
Solution
As suspected ..
Do you see that small 100MB EFI System partition? That is bootloader partition.
Only drive containing bootloader is bootable. That is your 120GB drive.
M.2 drive doesn't have a bootloader, so it is not bootable.

Execute following commands from elevated command prompt. Regular command prompt will give error on last command.
(if you get any errors, then stop immediately)
diskpart
list disk
select disk 2
list partition
select partition x
(select 931GB partition, x=1 or x=2)​
shrink desired=500
create partition efi
format fs=fat32 quick
assign letter=H
exit
bcdboot C:\windows /s H:
After this is done shutdown, disconnect sata SSD, change boot priority so Windows Boot Manager on M.2 drive is first in boot order and test, if your system can boot into windows.

Here's, how to open elevated command prompt:
Hi this worked! Thank you so much! I couldn't find any other solutions about this anywhere.

Just a question, since this was a newly built PC from scratch, if I built another PC with an M.2 SSD, would I have to insert that M.2 into a working computer and do all these partitions on it first before putting it in a newly built PC?
 
As suspected ..
Do you see that small 100MB EFI System partition? That is bootloader partition.
Only drive containing bootloader is bootable. That is your 120GB drive.
M.2 drive doesn't have a bootloader, so it is not bootable.

Execute following commands from elevated command prompt. Regular command prompt will give error on last command.
(if you get any errors, then stop immediately)
diskpart
list disk
select disk 2
list partition
select partition x
(select 931GB partition, x=1 or x=2)​
shrink desired=500
create partition efi
format fs=fat32 quick
assign letter=H
exit
bcdboot C:\windows /s H:
After this is done shutdown, disconnect sata SSD, change boot priority so Windows Boot Manager on M.2 drive is first in boot order and test, if your system can boot into windows.

Here's, how to open elevated command prompt:
DUDE. FREAKING GENIUS MAN. I've been at it all night. I never would have checked this because this was my boot drive on my old machine, but also had a 3.5inch with the EFI partition.