I have an Asus Ultrabook S400CA-DB51T and I want to replace windows 8 with ubuntu. No dual boots or anything like that, just 100% ubuntu.

I'm trying to make the conversion with the 13.10 image, but I'm running into some issues. The automatic installation tool doesn't seem to recognize the 24gb SSD where windows 8 is installed - just the 500gb data HDD. When I go into the something else option to manually configure the installation myself, I'm hit with about 6 partitions in the 500gb HDD and 2 in the SSD. That kind of blows my mind since it's a brand new laptop, but I figured they were all recovery partitions and other stuff that I didn't need anymore. So I deleted all of the partitions, but I'm not sure how to now format the two drives.

My instinct was to format the HDD as ext4 pointing to /, and the SSD as ext4 pointing to /boot, but I'm getting the following message:

The partition table format in use on your disks normally requires you to create a separate partition for boot loader code. This partition should be marked for use as an "EFI boot partition" and should be at least 35 MB in size. Note that this is not the same as a partition mounted on /boot.

And I'm not sure how to really progress from here. I don't know what a Reserved Bios Boot area is, and where that partition should go. Any help would be much appreciated, thanks guys.

  • 1
    Can you disable EFI through bios? If you aren't doing dual boot then you really don't need to keep it.
    – DavidGamba
    Commented Jan 31, 2014 at 14:29
  • I'm not 100% on how to do that through the bios. I've got secure boot off, but I'm not sure how to just disable EFI.
    – Alex
    Commented Jan 31, 2014 at 14:37
  • Disabling secure boot is exactly what I meant. Are you having that issue even after disabling secure boot?
    – DavidGamba
    Commented Jan 31, 2014 at 14:40
  • Yes I am. Would creating a 200mb partition on the SSD using the uefi boot flag under ubuntu be a viable move? Or would disabling secure boot render that a weird situation?
    – Alex
    Commented Jan 31, 2014 at 14:53
  • Haven't had that problem before, the one thing I do know is that some bios can't read /boot partitions bigger than 1GB, so you should also reduce the size of that partition.
    – DavidGamba
    Commented Jan 31, 2014 at 15:04

2 Answers 2


I would not fiddle in the BIOS and and disable SecureBoot/UEFI. Some newer systems won't even allow to do so!

Also, it is quite easy to setup UEFI-compatible Ubuntu:

Put on SSD:

  1. Boot partition: /boot, ext4, 512MB
  2. EFI boot partition: /boot/efi, fat32, 128MB
  3. Root partition: / ext4, rest of ssd

Put on HDD:

  1. Home Partition: /home, ext4, full size

More information, although imo lacking some good overview: https://help.ubuntu.com/community/DiskSpace

EFI partition:

  • Mount point: /boot/efi (no need to set up this mount point as the installer will do it automatically) Type: FAT (generally FAT32)

  • Description: the EFI partition (also called ESP) contains some boot files. It is necessary if the firmware (BIOS) is set up to boot the HDD in EFI mode (which is default on more and more modern, > year 2011 computers). It must be located at the start of a GPT disk, and have a "boot" flag.

  • Size: 100~250MB


If I were you I would create a single partition on the SSD, format ext4 and mount it at /, create a single partition on the HDD format ext4 and mount it at /home. You will likely have to play with the BIOS options to turn off SecureBoot and/or UEFI as well as choosing the SSD as the Boot device. Install grub into the MBR of the SSD

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