Craig Sanders <cas@taz.net.au> writes:
The latest debian installer fully supports installing to GPT on UEFI systems - the catch is that to load the efivars kernel module (needed so that grub-efi-amd64 and efibootmgr can update the efi boot table), you have to have booted a UEFI boot-loader.
AIUI this is the key problem -- currently debian-installer does a UEFI-style install iff bootstrapped from UEFI. I don't know if there's a workaround (other than BIOS/GPT, which you note breaks Windows). If you do IRC, ask #debian-next or #debian-boot (OFTC) about it. There are "daily" and periodic "testing" builds of d-i that may work better than the stable build. (IME usually not, though :-) http://d-i.debian.org/daily-images/amd64/daily/netboot/debian-installer/amd64/{linux,initrd.gz} http://ftp.debian.org/debian/dists/{testing,unstable}/main/installer-amd64/current/images/netboot/debian-installer/amd64/{linux,initrd.gz}
(apparently there is an alpha-quality syslinux 6.x series which will be efi)
Likewise on #syslinux (Freenode, IIRC) I've found hpa et al to be patient and helpful, they may know of some workaround that I don't.
I could have disabled UEFI entirely and had far less problems [...]
This is the approach I have been taking. http://www.cyber.com.au/~twb/snarf/extlinux-gpt.page (not needed if you use grub, as d-i sets up grub correctly under BIOS/GPT)