Cannot boot from a bootable flash drive when using Win10 with UEFI

I’m using a Dell i3670 purchased new a few months ago. Win10 and EUFI are factory installed. The computer runs fine.

How can I boot/restore using an image file on a flash
drive?

With BIOS/MBR, it was easy. I changed the boot order so the flash drive was checked first. If a flash drive was connected to the USB port, it booted or at least started, and normally I was asked to specify the external drive containing the image file, etc. If I accidentally used a non-bootable flash drive, the screen said “no system”

UEFI is a different story, and I tried two approaches. In both cases, I had a legacy Bootable Flash
drive connected to the most likely boot port. I don’t know which of two ports is correct, but tried to use both most potential ports.

Choice 1: I used F2 during startup, and the setup screen appeared. I went to Settings>General>Boot Sequence. Normal choices are Windows Boot Manager, Onboard (IPV4), and Onboard (IPV6). There is also a Boot Option area where UEFI and Legacy can be selected, but legacy is greyed out.

I clicked Add Boot Option, and the Boot Option window appeared,
with three places to list information:

Name the Boot option

File System, which lists:
PciRoot(0x0)/PCi(0x7.oxo)/Sata(0x1/HD(1.gpt,8382e$ba-20e4-4ES8-8A7S-B7PC2408X764

List the file name

I didn’t know what to do, so stopped.

Choice 2: Settings>Update and Security>Recovery>Advanced startup>Restart Now>Three choices appeared. I selected "Use a Device". Comments for this choice said: “Use a USB device, Network Connection, Windows Recovery DVD”.

Three choices were given:

UEFI DVD +-RW DU-8A5LH
Onboard NIC(IPV4)
Onboard NIC(IPV6)

I did not have a DVD with a UEFI format, but tried a
legacy bootable DVD, which did nothing. I tried IPVV4, and the computer started normally, not from the flash drive.

Jim

What are you trying to do? In uefi systems if it has secure boot set it wont allow you to boot and change any system that isnt in the database

I want to backup my computer by creating an image file using EraseUs or Macrum and be able use it to restore in the future, if needed. I'm sure there is a tutorial on this topic in the Tutorials, but have been unable to find one. Those that I found appear to be for BIOS/MBR computers. In the past when I used BIOS/MBR computers, an early step was to set up the computer to boot using a flash drive, which applied to my request.
Jim

First, I would suggest you create a restoration flash drive for the current computer with the program you want to use to make backups. Then you want to enter the boot override menu when you try to boot from the USB flash drive, which is usually accomplished on UEFI computers by repeatedly pressing the F12 key at first signs of the manufacturer's logo (with the flash drive plugged in). If you created the USB flash drive from your backup program currently installed on your computer, it should create one compatible with UEFI.

As already said, create a bootable usb. I don't use EasUS, but I know Macrium will include uefi boot support on its rescue media.

Then use F2 to go into the bios and make sure that Secure Boot is turned off.

I had a legacy Bootable Flash drive

Create it again and format it as fat32 instead of ntfs, then it should boot using uefi/secureboot.

@Jim
Post #1: I had a legacy Bootable Flash drive
Post #3: I want to backup my computer by creating an image file using EraseUs or Macrum and be able use it to restore in the future, if needed.
I suspect it would be best to create a bootable flash drive designed for your UEFI system as has been discussed.

I solved by changing hard drive sata port on mother board (after testing all bios settings, drivers, boot fix and registry change).
On the new sata port hard drive booted well without usb key plugged.
At first login SSD hard drive was re-detected inside windows and "re installed" by the system with a little message saying "PNY SSD install successful" bottom right.
Next restart worked fine.