booting UEFI without CSM on Dell Vostro 3550?

i'm looking at a friend's laptop, Dell Vostro 3550

I have a USB , hirensbootcd, with GPT partition with EFI directory. it's WinPE based. I made it in Rufus from an iso from https://www.hirensbootcd.org/download . It boots fine on my Hp Probook when I go to the HP Probook's BIOS options and choose to boot off it and I choose the .efi file on it to boot off of.

But when I try it in the Dell Vostro 3550, it says

"Error legacy boot of UEFI media" "This device can only boot in UEFI mode, it can not boot in BIOS/Legacy mode. If you want to boot this device in BIOS/Legacy mode, you should recreate it in Rufus using the following settings. partition scheme-MBR, Target system-BIOS."

I'd have thought the easiest thing is to set the UEFI to regular, not CSM./legacy But I see no option in the UEFI for that.

The UEFI says Aprio setup utility, american megatrends. It says BIOS Version A07. It has tabs "main, advanced,security, boot, exit" maybe i'm not looking in the right place, but I can't see an option .

No doubt it's a UEFI Not a BIOS, since this is not the 1990s(the processor is an i3), but is it possible that it only runs with CSM, and has no option to boot as (regular) UEFI?!

 

from what I heard, computers made between 2000-2010 that isn't a mac, had, or often had, UEFIs that only supported legacy mode.. (Pnor full uefi )

That computer has an i3 process,the i3 was 2010, so that laptop is close to 2010 so maybe it does indeed only offer legacy mode, hence no option given re legacy mode.

So I guess the first decade of UEFIs only supported legacy mode.