I received my 512GB Steam Machine yesterday and immediately attempted to follow the standard instructions for upgrading storage: replace the physical drive and then run the SteamOS recovery image from a USB drive.
That method failed, the script for reimaging failed when mkfs couldn’t do … something. The error was a little ambiguous and searching yielded no obvious solutions.
I’ll include the various search terms here in case it helps someone find it later: “discarding device blocks” stuck “mkfs input/output error”
Note the 2TB NVMe I installed had a Bazzite install on it, but I’d expect the script to handle that. Even deleting all the partitions manually in KDE Partition Manager (included in the recovery image) didn’t help. But you may not have an issue with a truly fresh drive. I reinstalled the original 512 drive and proceeded to setup the device and install some games.
What DID work is to use a Rescuezilla image to clone the OG drive onto the 2TB while the OG drive was installed in the SM and the 2TB in a USB enclosure. With 400GB of game data, it took around 15m. Then using Gparted in Rescuezilla, I increased the size of the final partition to use up all the remaining space.
Be sure to use the front USB-A ports, they are 3.2.
This is the video guide I used: https://m.youtube.com/watch?v=jCxJYtE5ONE
Now I can play games instead of just installing them!


Thanks for sharing, hopefully it will help someone.
From reading on the issue, it may be a timeout during a large TRIM operation. With larger drives, you can have large scale TRIM operations fail for a couple reasons, but it mostly comes down to the volume of the requested consecutive operations being more than the NVME drive’s controller can handle in one go, or more than it can handle within the typical 30 second timeout window for these commands.
If it was this, you could either temporarily disable trim for the drive before running the install, or possibly tweak the mkfs commands in the install script to include the nodiscard option.
Interesting, and good to know. I couldn’t find any such information when searching.
I think the clone in place solution is superior in any case as the Rescuezilla image is a bit more mature than Valve’s “Arch with some scripts” recovery image. It also transfers installed games, and only needs the additional NVMe enclosure.