Help Needed Install on ASUS Prime Z270-A

[artche]

Hi guys, I have same machine
ASUS Prime Z270-A
i7-7770K 4.2ghz
ASUS GTX 1060 - 6gb STRIX
HDD WD 3TB
SSD Samsung 256GB
Corsair RM 750X

HDD - Win 10

and want Sierra on SSD

and I have this problem

 

[EricDi]

See other thread you posted in.

 

[BreBo]

@artche, please update your profile (personal details) with your Motherboard or Make/Model, CPU and Graphics Card.

Profiles need to contain at least your primary system to assist others with helping you.

"Still waiting for root device".
When installing this means that your USB flash drive cannot be found.
This is usually because the flash drive is in a USB3 port.
If this is the case move it to a USB2 port, if it is already in a USB2 port move it to another and try again.
Repeat until you have tried all USB ports.
Use a USB2 flash drive.
If it still doesn't work you could try another flash drive.
You might also try enabling Legacy on your USB3 ports in your BIOS settings.
Make sure Fast Boot is not activated in your BIOS.