USB3 3TB HDD boot

[Bob Lemar]

Hi, guys

I got new SEAGATE Expansion USB 3.0 and want to boot linux from it.

I have successfully booted various linuxes before with different
loaders from USB thumb flashes. But I cannot do it with this external
drive.

There are three problems: USB3, 4K sectors and >2TB.

I try grub2 (fedora 17). Grub2 doesn't power on external USB drive.
The drive is spinning up only after some OS is starting to load after
grub2. So grub2 and BIOS don't see external HDD.


Can someone point me out:

1. either how to turn on external USB3 driver while computer is in grub2?

2. or how to load OS with kexec from external USB3 4K sector drive
(from OS which is located at internal HDD)?

--
Best regards, Bob