Need to reboot twice for POST & grub menu

yeah, but there is no POST screen and GRUB menu on first reboot. so i cannot choose windows from GRUB menu or even enter BIOS setup, it’s appear on second boot.

i understand. enabling or disabling Fast Startup (hibernation) on windows should in no way affect how Linux reboots. It’s disabled anyway.

i think i started in the wrong way. forget GRUB , let’s focus on POST (power-on self test)

Before I finally give up I will write it again in a different way.

The computer is off → I boot the computer → POST screen appears with ASUS ROG logo (I can then go into bios settings) → linux loads. then I reboot and there is no POST screen anymore but linux starts right away, I give another reboot and I have a POST screen and then a menu appears with system selection (GRUB). I shut down the computer.

The computer is shut down → I start the computer → POST screen (power-on self test) screen appears with ASUS ROG logo (I can then enter bios settings), from GRUB menu I select WIndows - windows loads. I give restart and POST screen appears and then GRUB menu appears and I can choose which system I want to boot. and so every time unlike Linux where I have to reboot twice.

question - why i don’t have POST screen on linux after every reboot and on windows i do?

i can also live with it. it is not terribly inconvenient.