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 (/dev/sdc):

# 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.

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    your problem is probably the way you did the copy. the efi is smart enough to know a usb disk is not a cd, and so it doesn't much care for the iso fs there. there's also the weird hack most distros do the boot live either way - they do a loop mount thing to fool the efi into finding an esp. its ugly - and prone to err. just format the stick fat32 and copy the tree over. you might want to loop mount the efi image and extract the efi kernel and initramfs though. alrernatively, install rEFInd from windows and you can boot anything.
    – mikeserv
    Dec 29, 2015 at 6:11
  • @mikeserv thanks for your suggestion, mike. Luckily, DVD image did the trick, while CD image, apparently, doesn't support 32-bit UEFI. Got my Jessie up and running as well as Windows 8.1. Dec 29, 2015 at 9:41

1 Answer 1


Yes, the problem was that CD image of Debian 8 apparently doesn't support 32-bit UEFI boot, while DVD does. So, I had to download a 3.7 GB DVD image and create a bootable USB stick of it the same way I did with CD image.

From that USB stick I successfully installed Debian and GRUB in ESP. Upon boot, GRUB menu offers to chainload Windows 8 bootloader and both Debian and Windows 8.1 work fine.

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