EFI Chip Location - Want the old Serial number back

Hello everyone,

in my previous thread I talked about the water damaged MacBook Pro 13" of my aunt. Since I want to repair it for her I might need a new logic board if the repair of the water damaged Logic Board fails. But she wants the old serial number back which is also found on the bottom cover of the MacBook so now I am in a dilemma.

After some research I found a video where a guy shows on an older MacBook how he changed the Serial by de-soldering the Bios/EFI chip and editing the value with an HEX Editor. But since I have the water damaged board here I could simply desolder the EFI Chip and put it on the new Logic Board if it's the same spec like the water damaged one right?

So could anyone show me where the EFI Chip is located on the Logic Board? I can upload a picture of the water damaged one of my aunts MacBook and you guys could take it and circle it with an photo editing software like paint or something else? Or I think the Hi-Res Images of iFixit's teardown of this model are way better? Just let me know :-)

Cheers to anyone helping me out of this dilemma and OCD triggering of my aunt x)

I think I might found where the EFI Chip is located at.

The Chip on mine is a MXIC Chip with the Model Number: mx25l6473ezni

And the new Logic Board has an Winbond SpiFlash W25Q64FV on it.

Are these interchangeable? And are these even the EFI Chips on these machines? Because if yes that would be awesome and my aunt would be happy again :-)

Here is an image of iFixit where they marked the Winbond SpiFlash W25Q64FV chip in Green:

Would be awesome to hear some feedback on this so I know that I am on the right path. Getting into this whole board repair thing feels good because I get to understand even more and more how these machines work by actually looking at each individual parts.

Cheers :-)

Edit: Do I need to reball these chips? Because a guy on YouTube (Louis Rossmann) seems like he get's rid of the lead free solder and adds leaded solder and heats the chip up with his hot air rework station and pushes it down on the right spot. Easy as that? Or is there a catch to this?

Seems like just swapping the EFI Chips is not enough.. I would have to edit or clean the ME Region of the chip because the current ME Region on these EFI Chips are paired to the current motherboard. It's like a handshake between the CPU and Ram etc. as far as I understood. I would need to erase that part so the efi chip thinks it's a new one so it marries the "new board" and works. Seems like getting an programmer to edit the chip that is found on the replacement logic board to change the serial to the one on the bottom cover is way easier then doing all these steps above. Anyone can recommend any programmer for this specific job? Thanks :-)