Windows 10: switch Legacy to UEFI

have Dell Inspiron 660, A12 BIOS 3/20/2018 currently have Legacy with Secure Boot disabled If I change to UEFI with Secure Boot enabled will W10 20H2 start up correctly? thanks (saw the W11 stream today)

:)

 

UEFI or Legacy?

So i went for a clean Windows 10 installation on my Aspire E13.
To boot from USB i had to switch from UEFI to Legacy, otherwise the USB drive would not be listed.

However. After the installation was finished my touchpad was not even recognized, i mean, i was not even listed in the device manager, so i read somewhere on the Acer forum that switching back to UEFI would solve this problem.
Well, i switched back to UEFI and now when the laptop start i recieve a message that says -No bootable device found!

Even if i try to use my bootable USB drive, the list is empty.
So i switched back to Legace again and guess what. Windows 10 starts like there was no problem.

So, what's the different between UEFI and Legacy? The bios tells me -Use UEFI on Win 8 and above to use all the benefits.
And why oh why can't i boot up from a existing and working Windows 10 drive using UEFI?

 

Legacy to UEFI

I'm debating moving to UEFI form my now legacy BIOS (Award Software Int.) the mother board is a GA-Z68XP-UD3 rev1.0 on the the following link it shows a UEFI BIOS U1J )UEFI BIOS)

https://www.gigabyte.com/Motherboard/GA-Z68XP-UD3-rev-10#support-dl-bios

Currently I'm running the legacy F10 BIOS. Does installing the UEFI BIOS automatically take care of everything to get to the UEFI BIOS? Installing the UEFI BIOS following the instructions using the Q-flash method GIGABYTE How to Reflash Motherboard BIOS

What's steps do I take and in what order?

Much appreciated

 

UEFI or Legacy?

Depending how the Windows 10 install media is booted (UEFI or Legacy BIOS) Windows Setup creates either GPT or MBR partition style on the hard drive.

First, check the file system of the USB flash drive.

The file system of the USB flash drive must be FAT32 if you want to install Windows 10 in UEFI mode.

USB Flash Drive - Create to Install Windows 10

Option One: Use Media Creation Tool to create Bootable Windows 10 USB for Legacy BIOS and UEFI
Option Two: Use "Rufus" to create Bootable Window 10 USB for Legacy BIOS and UEFI