Soldered RAM replacement is a pro-only job.

You probably shouldn’t do this yourself unless you already have a microsoldering setup and the experience to use it.

The tools aren’t cheap: a proper hot air rework station (not a heat gun), a temperature-controlled soldering iron, flux, solder wick, a microscope or strong magnifier, and a BGA reballing stencil set. You’ll also need low-melt solder and a preheater for the board. Total cost easily over $500 for halfway decent gear.

The skills are the real barrier. You need steady hands, patience, and the ability to reball BGA chips without bridging pins or lifting pads. Modern ultrabooks have multi-layer boards that soak up heat and can delaminate if you’re not careful. One slip and you’ve trashed the motherboard.

If you absolutely have to try it, practice on a dead board first. Otherwise, paying a pro a couple hundred bucks is cheaper than replacing the laptop.