TeraByte Unlimited

Model: Surface Pro (5th Gen) - 256GB i7 8GB M1796
BootIT UEFI 1.21 installed
BIOS settings: TPM "disabled", Boot: "MS and 3rd party CA"
Win 10 Pro installed without Bitlock.

I would like to Image main partition to USB key but no key is detected.

I could obviously previously boot from USB to install BootIT, but when run, no USB dectected within the program itself.

As far know, I can only save from one partition to another on same SSD.

Any advice?

Does Windows see the USB drive? You could try reformatting the USB drive in Windows and see if that helps (assuming it has some other type of formatting). Some USB drives have issues showing in UEFI. Have you tried plugging in the USB drive, booting into BIU, and then rebooting back to BIU?

If the Surface has a microSD slot (or other flash card slot) you could try saving to a card in that (assuming it shows up).

Alternatively, you could use TBWinRE or IFL x64. Both of those should see USB drives.

Solved.

in Surface UEFI | Boot configuration | Configure boot device order
must be in this specific order:

-USB Storage
-BootIt UEFI
-Windows Boot Manager
-Internal Storage
-PXE Network

If BootIt is first, both partition work and disk imaging won't see USB key. If USB storage is first (and not bootable of course), it will been seen.