Don't upgrade soldered RAM — you probably can't.

You can’t. Soldered RAM is fixed to the motherboard. No slot, no swap. A few shops will desolder and replace the chips, but that’s specialized work — expect $200–400 if they even take the job. For a 3–4 year old laptop, that money is better spent on a new machine.

If your laptop has soldered RAM, what you bought is what you get. That’s the trade-off for thinness. A new laptop with 16GB or 32GB will cost more, but you’ll get a faster CPU, better battery, and a warranty. The upgrade path for a soldered laptop is “buy a new one.”

One exception — if your laptop has one soldered stick and one open SO-DIMM slot (common on some models), then upgrading the slot is easy and cheap. Check your exact model before giving up.