Don't count on disabling soldered RAM in BIOS.

No, I’m not aware of any mainstream laptop that lets you disable the soldered portion to use only a socketed module.

The few laptops with both soldered RAM and a SODIMM slot (like some ThinkPads, Latitudes, or Dell XPS) treat the soldered memory as the primary channel. The SODIMM adds capacity, but the soldered RAM is always active. Even if the soldered module fails, the laptop usually won’t boot from the SODIMM alone — that’s not a BIOS toggle, that’s a hardware limitation.

There are edge cases: some Clevo resellers or older gaming laptops with two SODIMM slots might have soldered-on-board RAM for a specific configuration, but those are usually all-socketed or all-soldered, not hybrid. And even then, the BIOS rarely exposes a disable option.

If you need upgradeable memory, don’t buy anything with soldered RAM. Period. Framework, some ThinkPad T-series with two SODIMMs, or old-school gaming laptops are your only real options.