CastorisCausa

This post is about creating a UEFI-bootable full Linux installation in a USB Flash Drive or External HDD. For sake of simplicity, I'll refer to a USB Flash Drive or a USB External HDD as USB-disk. This procedure is performed in a computer running Windows without installing Linux in the HDD, therefore there is no modification (nor mess) in the Windows EFI partition. Here a nice explanation on how UEFI boot works.

First of all, if you're looking for Live-USB with or without Persistence with both Legacy and UEFI boot, a nice option in Windows is LinuxLive USB Creator. These are the differences between Live-USB with Persistence and a USB Full Install.

Process Big Picture

The procedure comprehends three main parts:

1. Creating UEFI-booting Virtual Machine, without (virtual) HHD
2. Installing Linux in the USB-disk
3. Modifying the EFI partition in the USB-disk

Requirements

• VMware installed
  The Workstation Player version is free for non-commercial use
• USB-disk, USB3 if your computer supports it I've tried the procedure with both USB Flash Drive and External HDD
• ISO image of your favorite Linux distribution

For the following steps an ISO image of Linux Mint 18.1 64-bit was used, similar instructions should apply for other distributions.

Procedure:

1. Creating UEFI-booting Virtual Machine, without (virtual) HHD

1. Open VMware and Create a New Virtual Machine

   
   
   

2. Select the I will install the operative system later option. Click on Next

   
   
   

3. Set Guest Operating System to Linux, select your version or the closest one, in my case the closest to Mint 64-bit is Ubuntu 64-bit. Click on Next

   
   
   

4. Assign a Virtual machine name and Location to the Virtual Machine. Remember these fields, and they'll used later. Click on Next
   

   
   
   

5. Disk Capacity, default parameters (this HDD will not be used). Click Next
   
   
6. Click on Customize Hardware
   1. For the New CD/DVD (SATA), Select Use ISO image file and browse for your Linux ISO image
      
      
   2. For the USB Controller, Select USB 3.0 (if supported), [X]Automatically ..., [ ]Show all... and [ ]Share Bluetooth...
      
      
7. Before completing the wizard, identify the Location of the Virtual Machine. Click on Finish. Do not power ON the Virtual Machine yet.
8. Go to the Virtual Machine Location, and with help of a text editor (e.g. Notepad), open the file VMname.vmx (where the VMname is the Virtual machine name assigned in step 4). And add the line firmware = "efi" at the end of the file
9. In VMware, open the settings of your brand new Virtual Machine and remove the HDD
   
   

2. Installing Linux in USB-disk

In the step, the Virtual Machine will boot in UEFI using the Linux ISO image, from there it'll possible to install Linux in the USB-disk.

1. In VMware, Power ON the Virtual Machine. When booting on UEFI, it should look as below (at least for Mint 64-bit). Select Start Linux Mint 18 Cinnamon 64-bit (or Try Ubuntu without installing)
   
   
2. Once the Linux session is started, connect (physically) your USB-disk, and be sure it's connected to the Virtual Machine
   
   
   

3. To start the procedure with a blank USB-disk. In the Virtual Machine, Open GParted (hopefully is installed). Then select your device at the upper right corner (remember its sdx), then go to Device > Create Partition Table, select the type gtp. Close GParted.

4. Click on the Install Linux (Mint) icon on Desktop.

   1. Select your language.
   2. Leave unchecked the option Install third-party software...
   3. In Installation type select Erase disk and install Linux Mint
5. One the installation is done, select Continue Testing

3. Modifying the EFI partition in the USB-disk

Still in the Linux session (Virtual Machine without HDD booted with Live-CD) from the previous section, the remaining part is to prepare the EFI partition on the USB-disk to make it UEFI-bootable

1. Create a folder /mnt/efi/ :::powershell $ sudo mkdir /mnt/efi/

2. Mount the EFI partition in the recently created folder. Change sdx for the corresponding to your USB-disk (step 4 in previous section)

   1 2	$ sudo mount /dev/sdx1 /mnt/efi $ cd /mnt/efi/EFI

3. Copy the ubuntu folder to the same location with the name BOOT

   1	$ sudo cp -r ./ubuntu/ ./BOOT/

4. Finally, copy the file BOOTx64.EFI from to the Linux ISO image to the BOOT folder in EFI partition of the USB-disk

   1	$ sudo cp /media/cdrom/EFI/BOOT/BOOTx64.EFI ./BOOT/

5. Shut down the Virtual Machine properly.

Congratulations, now your USB-disk should be UEFI-bootable

Finally, reboot your computer, and select the USB-disk (Partition 1) for UEFI boot.

I've try this method using an external SSD via USB and a Lexar USB flash drive without issues.