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Trying to put Ubuntu on a Dell Latitude 7290.

In Windows: The C drive had a large Fat32 partition which I shrunk to create some space for an extra (virtual, possibly?) partition on which to put Ubuntu 18.04.

I switched to legacy mode in the bios (it was in UEFI mode) and to boot from USB.

I booted the laptop from a (ext4-partitioned) USB stick, installed Ubuntu on the new partition (which I formatted to ext4) but I didn't do anything concerning UEFI or /boot; I just told it to mount the new partition on / .

Installation went fine, but I can't boot into the OS. Mashing Esc on boot-up and then F12 takes me to some text-based list of options, which just seem to me to be the same options the BIOS is offering me. I would like to add a new boot option, however this involves finding a file called something like GRUBx86.efi or something, and I've looked all around the accessible parts of the file system (in particular EFI/Boot/) and can't find it. I'm wondering whether this efi file is somehow on the partition where I installed Ubuntu.

I only have a limited grasp of this UEFI stuff. It's a shame that 20 years after I was struggling to make a dual boot system, I come back to this and find that it is still a struggle.

Google suggested that I instead install Ubuntu from a FAT32 drive, but we could never persuade it to boot -- we'd just get a flashing cursor.

We went back to Ubuntu on USB but I don't know how to tell if one of the partitions on /dev/sda is an EFI partition, or what I should be telling the Ubuntu installer to do with it.

Kevin Buzzard
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  • Summary of question then: my BIOS' explanation of legacy mode led me to believe that if I wanted to boot off a USB stick I was going to have to switch to legacy mode. The answer points out that this is not true. – Kevin Buzzard Jul 05 '19 at 08:24

1 Answers1

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You don't have to switch to legacy mode to boot the Ubuntu Live USB. It's a hybrid .ISO that works in both CSM (legacy) and UEFI mode.

It's not really an "EFI" partition but rather partitions are "MBR" (Master Boot Record) or "GPT" (GUID Partition Table). Generally speaking UEFI systems use GPT partitioned disks and CSM (legacy) systems use "MBR" partitioned disks.

The old days of "MBR" only allowed 4 primary partitions which could be divided into extended logical partitions. The new days of "GPT" allow many more partitions.

The important things to remember is most people suggest AHCI instead of Intel RAID is better to install Ubuntu. Also most people suggest Secure boot should be turned off.

Finally after installing you may still need to run boot-repair:

WinEunuuchs2Unix
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  • Many thanks. Here's what happened in practice. I put the laptop back into UEFI mode. I inserted the USB. I booted into the BIOS. I could see no option for booting to the USB. I rebooted and went back into the BIOS. The second time, it was there. I booted to the USB stick. I never went into legacy mode :-) – Kevin Buzzard Jul 05 '19 at 08:26
  • @KevinBuzzard It sounds like the USB stick needs to be recreated. https://itsfoss.com/create-live-usb-of-ubuntu-in-windows/ – WinEunuuchs2Unix Jul 05 '19 at 10:30
  • The whole thing was due to my misunderstanding of UEFI mode. The BIOS tips clearly said that legacy mode could be used for booting off USB sticks; I incorrectly inferred that UEFI mode could not. I read that one could guarantee that Ubuntu was installed in UEFI mode by formatting the stick as FAT32 but I was still using legacy mode at that point. We got it all working now. Thanks very much. I posted my problem, went to bed, woke up 6 hours later and you had solved my problem. Many thanks. – Kevin Buzzard Jul 06 '19 at 19:06