Talk:UEFI
Contents
pages
external links
- Ubuntu and UEFI on Lenovo Thinkcentre M92P
- UEFI Mode installation of Linux distributions on Thinkstation S30
Primary Partition or Logical?
Legacy BIOS has a limitation of 4 primary partitions and 2.2 TB per drive.
With UEFI, this limitation is now 128 primary partitions and 8 ZB (source: Wikipedia).
So you can choose either primary or logic partitions, UEFI will deal with them anyway. On my laptop, I have chosen primary partitions, it sounds proper than logic partitions on the same primary partition.
If you're booting in BIOS mode, you'll be limited by MBR's restrictions, which begin with a 4-primary-partition limit. This limit can be gotten around by creating a special type of primary partition, known as an extended partition, which serves as a placeholder for an arbitrary number of logical partitions.
If you're booting in EFI mode, you'll use GPT, which supports up to 128 partitions by default (and this value can be raised, if necessary). GPT doesn't distinguish between primary, extended, and logical partitions, although some partitioning tools still prompt for primary vs. logical status when you create partitions on GPT disk. (These tools then ignore what you say, since it's meaningless.)
UEFI Mode installation of Linux distributions on Thinkstation S30
Ensure that the SCU device is the set up as the first boot device in the BIOS Setup Primary Boot Sequence. Lenovo has documented this issue here.
Ensure that there is an entry in the UEFI Boot Manager labeled "Windows Boot Manager"
Add an Entry to the UEFI Boot Manager labeled "Windows Boot Manager"
The following can be performed after installation of the operating system. The instructions assume that the user has access to "Live" installation media, is able to boot from that media and issue commands at the shell. It is also assumed that the user has a basic understanding of Linux devices references. The operating system must have been installed in UEFI mode and GRUB2 (or another bootloader) must have created at least one valid EFI boot file on the EFI system partition.
Insert the Live installation media, shutdown and power off the system. Power on the system. Interrupt the boot sequence with Enter or F12 and select the live installation media for boot. Open a shell. Establish whether or not the Live installation provides the efibootmgr tool, if it does not, install the package that provides efibootmgr. As root, inspect the current configuration of the UEFI Boot Manager:
sudo efibootmgr -v
If there is already an entry labelled "Windows Boot Manager", the remainder of these instructions do not apply. If there is no entry, add one. For example:
sudo efibootmgr -c -d /dev/sda -p 1 -l '\EFI\ubuntu\grubx64.efi' -L "Windows Boot Manager"
Please note that the option provided to the -l option can be any valid EFI boot loader. Verify that the entry was added to the UEFI Boot Manager:
sudo efibootmgr -v
Set the desired boot order of the UEFI Boot Manager, for example if the boot loader for Ubuntu is 0000 and, Windows Boot Loader dummy is 0001, and remaining boot devices are 000A-000C:
sudo efibootmgr -o 0000,0001,000A,000B,000C
Veryify that the BootOrder variable has been set correctly:
sudo efibootmgr -v
Optionally, adjust the value of the Timeout option to provide the user with more time to interrupt the boot process, for example, to extend the timeout to 10 seconds:
sudo efibootmgr -t 10
Shutdown the system, remove the live installation media and reboot. After booting into the installed operating system, confirm that the BootCurrent variable has selected the correct loader and is behaving as expected. Please note, you may have to install efibootmgr in the installed operating system.
sudo efiboogmgr -v
If the above fails, consult the documentation of your boot loader and ensure that it is configured correctly. Also ensure that your EFI system partition is laid out correctly and formatted as FAT32.
