Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up.
Sign up to join this community
Anybody can ask a question
Anybody can answer
The best answers are voted up and rise to the top
After a mostly default installtion of “legacy” ubuntu 20.04 server iso (the none-live version) on an old laptop that uses BIOS boot method,
lsblk shows the following result:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 238.5G 0 disk ├─sda1 8:1 0 512M 0 part /boot/efi ├─sda2 8:2 0 1K 0 part └─sda5 8:5 0 238G 0 part ├─vgtest-root 253:0 0 237G 0 lvm / └─vgtest-swap_1 253:1 0 980M 0 lvm (SWAP) sr0 11:0 1 1024M 0 rom
2 questions, please correct wrong assumptions in my thought process in those questions as well.
/boot/efipartition “sounds” wrong to me in a BIOS booted system. My
understanding is that, /boot/efi is a folder on a hdd that UEFI
firmware can automatically find, read, execute. A
BIOS booted system shouldn’t need it.
dfshows that the
/sda1partition is empty and there is no content in /boot/efi either. Why is the
/boot/efithere? did I do something while installing the system? I vaguely remember getting prompted about “where would you like to install grub/boot” (couldn’t remember the exact wording) at the end of the installation , I am hoping that’s refering to the /boot/grub installed under the
The 1K partion that is
/sda2. have no idea what that is. I don’t believe that’s the “grub’s 1.5th stage, immediately after the 0th LBA”, as 1KB is not enough to contain grub 1.5th stage.
You are right about
/boot/efi. The bootloader for UEFI mode resides there, but if you boot in BIOS mode (alias CSM alias legacy mode), you do not need it. I think that the installer creates it anyway. This is a new ‘feature’ of 20.04.x LTS, we did not see it in previous versions (at least not previous LTS versions) installed in BIOS mode.
In order to be sure about the boot mode, you can run
test -d /sys/firmware/efi && echo efi || echo bios
The 1K partition is an extended partition, a workaround used in MSDOS partition tables in order to work around the limit of 4 (primary) partitions. You can have several logical partitions inside the extended partition. The size reported here is only the size of the address. Partition #5 is a logical partition inside the extended partition, and inside it there is an LVM structure with the root file system and swap.