BIOS

I volunteer at Willow Creek Community Church, Computer Connection. Where we fix up donated computers and then give them to school children. We got 24 old Micro Soft Surface tablets. Of that I manage to re-image 18 of the with a WCCC version of Windows 10. The other not so good. 2 do not show that they even contain a SSD (128gb) in them. One shows it battery at 255% charge. 2 never could turn on (trash).
One while it works great had Bit Locker (removed) and its BIOS/UEFI screen locked with a password.
Surfaces come with Windows 8, 8.1, or Windows 10 pre-installed in them. They have the ability to format themselves (restart/shift) bring them back to the original install OS.
When I ask MS Community about it I was told that unless I can get the donated person password there is not way it can be removed. I have been told that if I take out the Coin and then wait a few minutes and put it back that the password would be gone.
Except that the Surface is a seal unit and even if I did open it up without damaging the screen took out a few dozens screws and manage to lift the batteries inside, there is not coin battery inside.
What I read if I read it correctly that you can put into the Surface BIOS a password to lock the motherboard so that no one can add anything to the SSD or use the USB port. That with the proper password remove that lock on the BIOS board.
I do understand the reason being told that I'm out of luck with out the original password If I wanted to upgrade Windows 10 BIOS then that is another question and it can be done. Really?
Really!
Without the original password I'm stuck in the mud.
But with that password then the motherboard is unlock and I can upgrade it.
If a Surface operates the same way as normal motherboards then all I need is to re-flash the memory chip or in its Diskpart program possible reformat partitions sections of the SSD.
Otherwise only the original Windows 10 will be use that came with the Surface.
While that is a simple solution the USB port can not be use.
That built in security do you not love it !!!!!