Valve doesn't want you to do this but you can certainly try.
[h=2]What you need to know[/h]
- Valve has published its own teardown video of the Steam Deck.
- Opening it up isn't recommended, but it doesn't look difficult.
- The SSD is replaceable, though it's not the regular size you'd get for a desktop or laptop.
Full story from the WindowsCentral blog...