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I downloaded the RTM ISO of Ubuntu 15.04 (Vivid Vervet), and I created with the latest version of Rufus the UEFI/GPT installation disk. I tried to begin the installation in the UEFI-mode, but it doesn't recognize the USB, even when I defined the USB as the loading source.

Only after I defined in Dell Vostro 3460 the boot legacy support and disabled the Secure Boot the installation process has begun.

During the installation, I defined the following partitions:

  • /efi, (300 MB);
  • /boot, (200 MB);
  • /swap, (8.5 GB);
  • /, (15 GB);
  • /home, (the rest of the space).

The process has finished successfully. But when I tried to switch from the legacy mode to UEFI, I faced with the problem when the laptop doesn't load and suggests to check the loading settings in BIOS.

My question is how to install Ubuntu in UEFI/GPT mode on my laptop? Why the created installation USB-drive doesn't work. It's important to note, there is no such issue with the Fedora and Windows installations, both of them succeed to accomplish the installation in UEFI/GPT mode, the installation drive has been created by Rufus too.

Thanks.

Mike
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  • Probably better not to have separate /boot partition as it just is another partition to manage on size & whether filling up. But you do have to have a tiny 1 or 2MB unformatted partition with the bios_grub flag in gparted or ef02 code in gdisk. Then grub will install correctly in BIOS/CSM boot mode. Then you can convert install from grub-pc(BIOS) to grub-efi-amd64(UEFI). I add both efi & bios_grub to all new drives which are now gpt partitioned. Not a lot of space and gives flexibilty if I want to change boot method. – oldfred May 13 '15 at 22:32
  • What is the pro & contra of having the separate /boot partition? When I decided to define the separate partition for the boot, I read a couple of articles where was declined the need/advice to separately define such partition. – Mike May 14 '15 at 05:16
  • @oldfred, Here http://unix.stackexchange.com/questions/256/is-it-good-to-make-a-separate-partition-for-boot there is a discussion on this subject, as far as I understand the main reason for the separate /boot was the problem with large discs detection. Do I understand it correctly, with *Grub2* there is no more such need? – Mike May 14 '15 at 05:48
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    OLd BIOS, or very old BIOS as my system from 2006 had no issue, had limits that all boot files must be within the first 137GB of drive. Sometimes similar issues with external drives using USB to connect. But I normally use 25GB for / (root) and rest of drive as data or a new user may use /home. If you have a multiple TB sized drive you do want a smaller / or system partition for every operating system. Also efi partition should be near beginning of drive, but I think only requirement is that efi partition be inside first 2TB of a drive. – oldfred May 14 '15 at 14:36

2 Answers2

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I can't speak to Rufus. My personal preference is to use dd to copy an image to a USB flash drive, since this results in a medium that usually boots fine in both BIOS/CSM/legacy mode and in EFI/UEFI mode. That said, some computers choke on such media, which employ something of a Frankenstein's Monster approach to their layout. In other words, there's no "one-size-fits-all" approach.

If the system is installed but unbootable, you might try a USB flash drive or CD-R version of my rEFInd boot manager. If you can boot it, rEFInd should detect your kernel and enable you to boot Ubuntu, with one caveat: Because you used a separate /boot partition, you'll need to highlight your kernel in rEFInd, hit F2 or Insert twice, and add ro root={whatever} to your kernel options, where {whatever} is your root (/) filesystem's device identifier. For instance, it might be ro root=/dev/mapper/ubuntu-root or ro root=/dev/sda4.

If you can boot to Ubuntu in this way, you should be able to re-install GRUB or install rEFInd to get your system booting normally. Read up on efibootmgr and EFI boot loaders for Linux to learn more.

There are a number of issues that can cause the type of problem you're having. Often it boils down to buggy firmware. There are workarounds for such problems, but if you've got a buggy firmware, it's better to return the defective computer and tell the manufacturer why you did so; anything less is an invitation to the manufacturer to keep shoveling junk down your throat.

One final point: If you can boot more easily in BIOS/CSM/legacy mode than in EFI/UEFI mode, by all means use the former. There are advantages to EFI/UEFI-mode booting, but they're fairly modest, so you shouldn't feel compelled to use that boot mode if BIOS/CSM/legacy is easier for you.

Rod Smith
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Ubuntu's live media will boot both in legacy and UEFI mode, and the install is done in whichever mode is booted. Some machines will not boot USB unless secure boot is disabled, but that does not mean you have to go to legacy mode. Try that. Also read:

https://help.ubuntu.com/community/UEFI

http://askubuntu.com/questions/221835/installing-ubuntu-on-a-pre-installed-windows-8-64-bit-system-uefi-supported
ubfan1
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