I want to install Debian 8 in UEFI mode alongside pre-installed Windows 8.1 on my Acer laptop.
I created a liveusb on Debian 7 machine by copying Debian 8 ISO directly to the flash drive device (
# cp debian-live-8.2.0-amd64-gnome-desktop.iso /dev/sdc
(ISO downloaded from http://mirror.yandex.ru/debian-cd/8.2.0-live/amd64/iso-hybrid/)
I've got Windows 8.1 already installed. I disabled secure boot and fast boot in UEFI menu and Windows Control Panel. I have USB HDD, USB CD and USB FDD UEFI entries go before Windows Bootloader in UEFI boot order menu.
Still, when Legacy mode (i.e. BIOS compatibility) is disabled in UEFI, it starts Windows Bootloader, ignoring flash drive. If I switch to Legacy mode, it successfully runs Debian installer from flash, but I don't want BIOS installation of Debian, as it's bad to mix operating systems, installed in UEFI and BIOS modes, on one drive.
They say (1, 2) that UEFI firmware on these laptops is 32-bit (strangely), booting 64-bit OS, but Debian documentation says, they support such combinations: https://wiki.debian.org/UEFI#Support_for_mixed-mode_systems:_64-bit_system_with_32-bit_UEFI
UPDATE: I guess, I found the reason. I've carefully read the "Support for mixed-mode systems" paragraph and support for mixed-mode is available only for dvd and netinst images, not for cd, I used. Will try installing from DVD image and report the results.