I keep saying the same thing over and over about the EFI issues and Apple, think EFI as a computer for your car and what garage can fix it other then the dealer if you lost your keys or need to re program a part you replaced.
Apple and most tech companies have been turning to this trend to prevent frauds while at the same time your files maybe trapped on a encrypted drive soldered unto a motherboard bricked from a Catalina update and only a Genius Bar can help you with this.....and within time and way they are operating its likely impossible, my solution was to bring the computer to a apple reseller, in a town far away from a Genius Bar...they usually tell you the dirt on Apple but dont get me wrong, ALL tech companies fallow this trend now. you won't be able to even swap parts of your computer with out problems, not even soldering a bigger drive, more ram is possible.
all components register IDs and this Chip2 set is another ball game.
Certain countries prohibit this and Genius bars do return Catalina bricked computers but reports from people show they swore parts are not the same, swapped, re programmed to work with the same motherboard., example one owner posted comments on a reddit thread accusing the Genius Bar of lying about her magsafe power supply claiming it was only supplying 5v when this was debunked online by a number of techs warning people that their machines can get bricked and which countries take action., unfortunately the US won't.
So unless you buy a new machine your at risk if you upgrade to Catalina.