"physical block size is 2048 bytes, but Linux says it is 512" when formatting USB - How to create a bootable USB without this error

A command-line method to make a live USB for UEFI systems

Please note: this deletes all data on the target device.

Install prerequisite:

sudo apt-get install p7zip-full

Assuming the target USB is at /dev/sdb

(please check first with lsblk or gnome-disks or sudo fdisk -l and be sure you know what you are formatting)

Make sure the device has no mounted filesystem and unmount it if necessary, for example:

udisksctl unmount -b /dev/sdb1

Destroy existing partition table:

sudo sgdisk --zap-all /dev/sdb

Create new GPT:

sudo sgdisk --new=1:0:0 --typecode=1:ef00 /dev/sdb

Format as FAT32:

sudo mkfs.vfat -F32 /dev/sdb1

Check it:

sudo fdisk -l /dev/sdb

Should output something like:

Device     Start      End  Sectors  Size Type
/dev/sdb1   2048 15663070 15661023  7.5G EFI System

Mount the drive and extract iso onto it, replacing 'name-of-iso' with the actual filename of the iso you downloaded earlier

sudo mount -t vfat /dev/sdb1 /mnt
sudo 7z x name-of-iso -o/mnt/


sudo umount /mnt

Now reboot & enjoy Ubuntu ^_^

(Here's where I originally learned to do this.)

Here's how I solved the problem of getting this error when trying to reformat a USB after using it as installation media:

  • First open the Disks Application under Applications > Disks
  • Select the bootable pen drive.
  • There will be an option menu on top right corner
  • Select the Format drive option (CTRL + F)
  • A pop-up will be shown. Select 0 partition and format the disk
  • Now the disk will be empty but it will be not recognized by system. But you can see on Disks Application.
  • Select the pen drive and re-format it. Now the pendrive can be detect by any system.

The accepted answer is too complex to use, as it required lots of typing and remembering the particular disk name (otherwise you may end up with serious problem). Mine is super easy to implement.

It is found that the problem is due to a bug in usb-creator-gtk. It is setting improper block-size during the creation of bootable media.

If this bug affects you, you can mark it here : https://bugs.launchpad.net/ubuntu/+source/usb-creator/+bug/1589028