Hi,
I can confirm your error being replicated (Quickset, Fn+F2) using a modded A19 bios to enable the hidden UEFI feature.
However, I have to disagree with you, using the stock A19 bios never enabled UEFI, Windows 8 was installed using MBR.
I believe UEFI support for L702x is flaky at best, will depend how much effort DELL wants to put to support a legacy L702x product.
I guess the only alternative is to get a new Inspiron 17R SE ?
Jase