Several questions about installing gentoo with UEFI on

[whjeon]

OK. I've done some research and experiment, still don't understand a few facts about installing gentoo on UEFI mode.
(What I've done : Reading Gentoo handbook, Google search with keyword like 'gentoo uefi','gentoo uefi install', I finally installed on CSM)
(Also I'm not native English speaker, so If I'm using wrong word or grammar, Please,let me know and really sorry about that)

#1. Why minimal ISO file doesn't able to boot on UEFI mode yet?, are there any reason to?
-It's 2017 already. and I think BIOS is old, old, very old.

#2. If I booted with CSM bootable USB, Is it impossible to install UEFI gentoo?
-I tried several times but couldn't figure out the way. FInally, installed on CSM mode.
-"/efivars" directory. is it important factor for UEFI install? Asking this because when I booted with CSM USB, there was no /efivars directory.

#3. If below has any wrong point, let me know.

for UEFI gentoo
-RescueCD/USB
-P1=/boot-Fat32
-P2=swap-mkswap
-P3=/ -ext4
Grub with efibootmgr

#4 If I'm using UEFI linux already and burned uefi bootable usb correctly , then just pressing F2 while rebooting(booting to UEFI setting) should find my usb, right?

[charles17]

[whjeon]