How to make a UEFI-based bootable USB stick with Ubuntu mini.iso

Ubuntu mini.iso is useful when we want to build a system with minimal packages.
It is useful to make a bootable USB stick.
Below is how to make UEFI-based bootable USB stick with Ubuntu mini.iso.

Required package: 7-zip

You can get 7-zip with the following command;

sudo apt install p7zip-full

Now we will use “7z” command.
Two options are needed. “x” for extract and “-o” to specify output directory. If the directory doesn’t exist, 7z creates automatically.

  1. Extract iso image into a directory
  2. Now I want to extract images into “usbdisk” directory.

    7z x -ousbdisk mini.iso

    This will make “usbdisk” directory and extract into the directory. Note that no space is allowed between “-o” and target directory. I tried space or quotation, without success.

  3. Extract efi.image under boot/grub
  4. One more thing. In order to make the USB stick bootable with UEFI, we need to extract efi.img under boot/grub. This can be easily done with the following command. (You don’t have to change directory.)

    7z x -ousbdisk usbdisk/boot/grub/efi.img

    This command will extract efi.img, which will be “efi” directory under which bootx64.efi and grubx64.efi exist into the usbdisk directory.

  5. Copy the contents under “usbdisk” to USB stick
  6. Finally we just copy the contents under usbdisk to a USB.

That’s it. Now try to boot from USB disk.