Soldered RAM stays soldered.

No.

You cannot add a RAM slot to a laptop with soldered memory. The motherboard was designed without the traces, controller support, or physical space for a slot. This isn’t a software limitation — it’s a hardware layout decision made at the factory.

Even if you had the skills to reflow the chip and solder a new socket, the memory controller in the CPU often expects a specific configuration. Mixing soldered and slotted RAM would require a BIOS rewrite that doesn’t exist. And the cost of a motherboard swap (if one existed with slots) would be more than buying a different laptop.

Buy the configuration you need upfront. If you want future upgradeability, avoid soldered RAM entirely. Laptops with two SO-DIMM slots still exist — look for them before you buy.

Future you will thank present you.