Could not boot: operating system not found

Hello, All–

I’m migrating from xubuntu and am new to the opensuse forums. To start, I’d like to mark this solved, already. After installing opensuse on my sony vaio, my machine would not boot. My only message was that in the topic: Operating System Not Found.

Not being a guru, it took me about two weeks to find the solution. It did not help that all initial searches pointed to hardware. Also, my vaio is eleven years old. It’s strictly BIOS–not even EFI with a Legacy option. I spent a good deal of time trying to get the boot flags just right. Eventually, I decided to wipe my hard drive, give it a msdos partition table, and install opensuse, again. I used a video tutorial to manually partition my hard drive. Once finished, I pressed the button to accept the partitions and their memory allocations. Only after this was I informed that a kernel could not be loaded onto a boot partition with such a small amount of memory.

The video didn’t specify how much memory to assign the boot partition, so neither did I. The installer automoatically assigned 1 MiB. After a quick internet search, I gave the boot parition 500 MiB of memory. My computer has been booting ever since.

I hope this helps the opensuse team and prevents anyone from getting the same headache I had. I’m looking forward to my new adventures in the world of openSUSE!


It’s easy to mix up “/boot/” partition and BIOS Boot partition” (bios_grub in parted parlance). The former can be used on both legacy- and GPT-partitioned disks. It needs a Linux native filesystem that mounts to /boot/, with enough space to store kernels, initrds and various other OS-boot-related files. Its use isn’t very common any more, except on systems employing RAID and/or LVM.

A “bios_grub” partition is typically a mere 32 sectors long, with no filesystem. It provides a place to install Grub on a GPT-partitioned disk, in lieu of the normally otherwise empty MBR track, because that space is consumed by the GPT partition table, leaving no place to install the Grub code stored in that track on a legacy-partitioned disk.

What follows is from a GPT-partitioned disk that includes a /boot/ partition for use in a legacy (non-UEFI) BIOS laptop:

DFSee Linux  17.0 : executing: fdisk -r- -w-
Command timestamp : Saturday 2023-04-29 17:40:40
|ID |ux|Dr|Type, description|Format  |Related |VolumeLabel|OS2-LVM/BM / GPT / Crypt / additional in|  Size MiB |
+--[/dev/sda     GPT disk  1]--------+--------+-----------[Model=Hitachi HTS721]-------------------+-----------+
|42 |  |  |Fsp + GPT hdr/pta|-- -- --|-- -- --|- - - - - -|                                        |        1.0|
|42 | 1|  |EFI System  (ESP)|FAT32   |GPT/EFI |           |P01 EFI System  (ESP)                   |      320.0|
|43 | 2|  |BIOS Boot (noEFI)|        |unknown |           |P02 BIOS Boot (noEFI)                   |        1.0|
|44 | 3|  |Linux Data       |EXT2    |GRUB    |h6p03boot  |P03 Linux /boot                         |      800.0|
|45 | 4|  |Linux Swap       |SWAP    |LinuxV1 |SWAPSPACE2 |P04 Linux Swap                          |     2400.0|
|46 | 5|  |Linux Data       |EXT4    |Linux   |h6p05usrlcl|P05 Linux /usr/local                    |     4000.0|
|47 | 6|  |Linux Data       |EXT4    |Linux   |h6p06pub   |P06 Linux /pub                          |     8000.0|
|48 | 7|  |Linux Data       |EXT4    |GRUB    |h6p07s155  |P07 Linux / openSUSE 15.5               |     7200.0|
|49 | 8|  |Linux Data       |EXT4    |Linux   |h6p08s154  |P08 Linux / openSUSE 15.4               |     7200.0|
|50 | 9|  |Linux Data       |EXT4    |GRUB    |h6p09stw   |P09 Linux / openSUSE TW                 |     7200.0|
|51 |10|  |Linux Data       |EXT4    |Linux   |h6p10tbd   |P10 Linux / TBD                         |     7200.0|
|52 |11|  |Linux Data       |EXT4    |GRUB    |h6p11debian|P11 Linux / Debian                      |     7200.0|
|53 |12|  |Linux Data       |EXT4    |Linux   |h6p12home  |P12 Linux /home                         |     5709.0|
|55 |  |  |Fsp + GPT pta/hdr|-- -- --|-- -- --|- - - - - -|                                        |      0.546|

# parted -l
Model: ATA Hitachi HTS72106 (scsi)
Disk /dev/sda: 60.0GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt_sync_mbr

Number  Start   End     Size    File system     Name                       Flags
 1      1049kB  337MB   336MB                   P01 EFI System  (ESP)      boot
 2      337MB   338MB   1049kB                  P02 BIOS Boot (noEFI)      bios_grub
 3      338MB   1177MB  839MB   ext2            P03 Linux /boot/
 4      1177MB  3693MB  2517MB  linux-swap(v1)  P04 Linux Swap
 5      3693MB  7887MB  4194MB  ext4            P05 Linux /usr/local
 6      7887MB  16.3GB  8389MB  ext4            P06 Linux /pub
 7      16.3GB  23.8GB  7550MB  ext4            P07 Linux / openSUSE 15.5
 8      23.8GB  31.4GB  7550MB  ext4            P08 Linux / openSUSE 15.4
 9      31.4GB  38.9GB  7550MB  ext4            P09 Linux / openSUSE TW
10      38.9GB  46.5GB  7550MB  ext4            P10 Linux / TBD
11      46.5GB  54.0GB  7550MB  ext4            P11 Linux / Debian
12      54.0GB  60.0GB  5986MB  ext4            P12 Linux /home

For this legacy BIOS use, the ESP partition is not required or used. It was placed there as a reservation in order that the disk might be migrated to a UEFI laptop without need to re-partition.

Firstly, welcome to the openSUSE Forums.

Usually, with a blank disk, the openSUSE Installer will automatically assign 512 MiB to the EFI System Partition (ESP).

Assuming that, your Laptop has a system disk of less than 12 GB, the installer will no longer automatically size the partitions – <>.

But, the ESP size should be setup as follows – <>.

  • It’ll depend on the Laptop’s BIOS –
    If an “old” UEFI then, a 16-bit FAT partition.
    If a current UEFI then, a 32-bit FAT partition.

Apart from that, if you really need to have a small ESP then, a FAT-16 or FAT-32 partition size of 260 MiB is sufficient.