U M 20.04.1 64bit Desktop installer problems

Successfully created a DVD of the U M 20.04.1 64bit Desktop iso. On legacy Intel 64bit Pentium with 16GB memory Gigabyte motherboard. I created an empty GPT on 250GB SATA disc. Booted the DVD and ran the installer. I ran into a number of problems trying to create "workable" partitions appropriate to this hardware. Three (3) attempts resulted in the installer failing near the very end. Only when I used the disc partitioning option of "Erase disk and install Mate" did the installation complete. But this only resulted in a VERY strange disc with an MBR (not GPT), NO swap and strange partitions!

  1. Manual GPT partitions...
    a. Normal installation and created part 1 100MB, phys, ext4, format, /boot.
    this resulted in a mysterious untyped,unnamed 1 MB partition PRIOR to the one created.
    b. created part 2 16000MB, phys, swap, from end of spare
    c. created part 3 remaining, phys, ext4, format, / (for about 230MB)
    d. near the end of the install of files error dialog popup"Error installing linux-image-5.4.0-47-generic package post-installation script subprocess returned error exit status 1".
    Why is an unnamed, empty 1MB partition automatically created PRIOR to the manually created first partition?

  2. start over... Normal installation and "Erase disk and install Mate".
    a. I get 2 creating partitions messages. I missed the first. But then got a strange install message where it says creating partition 5 as ext4. Why is there a default that has 5 partitions?
    b. File installation continues to completion without error.

  3. fdisk immediately upon installer completion report a VERY strange layout:
    a. the partition table is an MBR (dos) and not GPT
    b. sda1, part 1, phys, bootable, Id b, W95 FAT32, 512MB, mounted at /boot/efi
    What? There is no efi on a legacy system. Why is this created and mounted this way?
    c. sda2, extended, part 2, Id 5, 232GB, no mount point. This starts at the end of part 1 and contains the rest of the disc. what is this for? It has no filesystem. Why?
    d. sda5, phys, part 5, Id 83, Linux, 232GB, / mount point. This ALSO starts at the end of part 1 and contains the rest of the disc. It is IDENTICAL in start and length of the extended part 2! How can this be?
    e. There is NO SWAP space! How can this be?

Can someone explain these errors when using a GPT, the strange installer-created MBR and crazy partitions and NO SWAP?

Better yet, how do I create a sane GPT and partitions for this legacy system?


Welcome to the community @oldunixguy.

My knowledge on partitioning schemes is not deep enough to answer authentically but I can answer few of your questions.

Is that 1MB partition or just free space left in the beginning? I could possibly be protective MBR. I am not sure though. I have seen such 1MB spaces created otherwise also when creating partitions on multiboot setup.

I saw similar failure message (towards the end) when trying to install Debian on an old hardware. Maybe it is due to missing bios_grub partition. If you are trying to create a GPT partioning scheme on a BIOS hardware, one that does not support UEFI, you have to create a BIOS boot partition, and should have 'flag' named, bios_grub.

This is MBR (Windows style) artitioning scheme and partition 5 is your first logical partition. This is old partitioning scheme where the harddisk can have only 4 'primary' partitions and if you needed additional partitions, then (only) one of the partition will be treated as an 'extended' partition which can have several 'logical' paritions inside it. The new GPT partitioning scheme allows more than 4 primary partitions.

As far the installer goes, I've seen previously the automatic partitioning would create a large partition for system and a logical partition (e.g. sda5) for swap. The newer ones create one partition of type FAT as EFI System Partition (e.g. sda1) usually 512M and rest of the partition (e.g. sda2) for system (primary parition). No swap partition. What you have mentioned is bit confusing for me as well, because I have not seen a combination of MBR with one partition mounted as /boot/efi.

Ubuntu now uses swapfile instead of swap partition. If you open up a terminal and enter ls -l /, you will see a file named swapfile.

If you really want a different setup then,
i. sda1 - 1MB, do not format, set it as bios_grub(I am not sure if installer has this option, you may have to use Gparted)
ii. sda2 - as large as you want, for system and
iii. sda3 - optional for swap
No EFI mount points here.

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