This article was updated at 12:09 BST.
However, the developer notes that the SSD drives are “not intended for end-user replacement”, so it’s not yet clear if users will be able to successfully replace them.
It will begin shipping in December and come in three versions; 64GB eMMC ($399), 256GB NVMe SSD ($529) and 512GB NVMe SSD ($649).
On Saturday, in response to questions from fans, Valve updated the official Steam Deck tech specs to confirm that “all models” use socketed 2230 m.2 modules, which it says are “not intended for end-user replacement”.
That means that, in theory, even owners of the cheapest $399 Steam Deck could be able to open it up and connect an SSD drive. 2230 m.2 models are one of the smallest SSD modules and are currently capped at around 512GB off the shelf.
Steam Deck is also an open PC, Valve has said, with the ability to install any software or connect with any hardware.
The handheld gaming PC runs SteamOS 3.0 and Valve claims that developers’ existing game builds will likely work right out of the box.
This week Epic Games CEO Tim Sweeney praised Steam Deck, calling it an “amazing move” by his company’s PC store rival for making the device open platform. Steam Deck can, in theory, access the Epic Games Store or Xbox Game Pass.
“Amazing move by Valve!” Sweeney enthused, adding: “A handheld PC/console hybrid running the SteamOS fork of Arch Linux, and it’s an open platform where users are free to install software or their choosing – including Windows and other stores.”
Sweeney’s Epic Games Store is considered one of the main rivals to Steam, having launched as an alternative PC digital storefront in December 2018.