Thank you very much

I need to flash the BIOS without removing the chip on a Dell Precision 5570 laptop.
I've two questions:
1. The main BIOS seems to be GigaDevice GD25R512MEY (at the back of the motherboard). But there are two other Winbond W25Q80DV chips (One at the front, one at the back of the motherboard). What are these two? EC and/or Thunderbolt? Do they need to be flashed as well?
2. I can't locate the CMOS battery anywhere on the motherboard. Is it possible that the standard battery is being used as a CMOS battery as well?
Regards