I upgraded the storage on my Legion Go S to a 4TB SSD and switched from Windows to Steam OS. Here’s how the process went, along with my experience using Steam OS for gaming on this device. Here is my video showing the installation https://youtu.be/w-6Ydj6-y-U
Preparing for the Installation
To start, I downloaded the Steam OS installation file from Valve’s official support page. Valve recommends using Rufus, a free tool available from the Microsoft Store, to turn a USB drive into a Steam OS installer. Since my new 4TB SSD previously had Windows on it, I used Disk Management to wipe the drive and set the file system to EXFAT to avoid any conflicts with the previous operating system.
Before installing Steam OS, Valve recommends disabling Secure Boot. I accessed the BIOS by holding down the volume up and power buttons simultaneously. Once in the BIOS setup, I navigated to More Settings > Security > Secure Boot and disabled it. I also disabled the built-in battery under Configuration > Disable Built-In Battery to prevent any accidental power-ons while disassembling the device.
Upgrading the SSD
With safety steps in place, I began the hardware upgrade. First, I removed three screws from the bottom of the Legion Go and carefully pried off the Deco cover. Underneath, I found three more screws that needed removing. I also popped off the top triggers and loosened the screws underneath—just enough to get access. Using a pry tool, I removed the back cover and gained access to the original M.2 2242 SSD. I unplugged the battery, swapped in my new 4TB 2280 SSD, and reassembled everything in reverse order.
If you’re planning to try this yourself, I highly recommend keeping the original SSD intact and installing Steam OS on a new one. This way, you can easily swap drives if you ever want to return to Windows.
Installing Steam OS
With everything reassembled, I connected the USB installer using a hub and went into the BIOS boot menu. Selecting the USB drive initiated the Steam OS installation. I eventually landed on the desktop install screen, clicked the icon labeled Wipe Device and Install Steam OS, and confirmed through the prompts. After a bit of waiting, the Steam OS install wizard appeared. I selected my language, connected to Wi-Fi, and signed in to my Steam account.
Setting Up TDP Controls and Tools
To manage power settings, I switched to desktop mode and installed Decky Loader from its official website. After downloading it, I right-clicked the installer, selected Execute, and set an admin password under System Settings > Users. I then ran the Decky installer again, selected the stable release, and followed console instructions to complete setup.
Back in gaming mode, I was able to access Simple Decky TDP from the Quick Settings menu. This tool lets me adjust wattage based on each game’s requirements.
Performance Benchmarks
Steam OS impressed me with its performance across several titles:
- Marvel Rivals at 800p with FSR3 in performance mode and low settings averaged 69 FPS; at 1080p, it dropped to 50 FPS.
- Black Myth: Wukong at 720p with FSR and frame generation enabled averaged 77 FPS; at 1080p, it ran at 66 FPS.
- Frag Punk at 900p with standard graphics settings hit 110 FPS, dropping to 88 FPS at 1080p.
- Cyberpunk 2077 at 800p and 30W TDP averaged 98 FPS with FSR3 and low settings; at 1080p, it dropped to around 69.5 FPS.
For battery-powered gaming at 15W:
- Marvel Rivals at 800p averaged 56 FPS
- Black Myth: Wukong at 900p averaged 67 FPS
- Frag Punk at 900p hit 80 FPS
- Cyberpunk 2077 at 800p averaged 76.9 FPS
These results show how well-optimized Steam OS is for handheld gaming devices. It’s efficient, fast, and delivers solid performance.
Dealing With Compatibility and Workarounds
Steam OS isn’t without its limitations. Some anti-cheat systems still don’t support Linux, which means games like Call of Duty won’t run natively. My workaround was using Nvidia GeForce Now. I downloaded the Steam Deck version of the app from Nvidia’s website, executed the installer, and added it as a non-Steam game in gaming mode.
Performance using GeForce Now was smooth with no major lag or stuttering—though that depends on your internet connection. The only caveat was a wait for shader loading in Call of Duty: Black Ops on the first launch.
Battery Life and Additional Tweaks
I tested battery life using Doom: The Dark Ages at 720p and 25W TDP. Starting at 99% battery at 11:38 a.m., it dropped to 41% by 12:59 p.m.—giving me about 1 hour and 35 minutes of gameplay with nearly half the battery remaining. That’s a respectable runtime for this wattage.
One small issue I encountered was that the RGB lights weren’t working. Not a big deal, but I wanted them on. After installing Decky Loader, I switched back to desktop mode, installed the HUESYNC plugin, and enabled LED control. From there, I was able to set a solid color and adjust lighting preferences.
Tools and Final Thoughts
To make the hardware swap easy, I used the iFixit tool kit. It came with everything needed for the upgrade—high-quality tools that are well-organized and ideal for handheld work. I’m not sponsored by iFixit, but I do have an affiliate link in the description if you want to check it out.
I’ve also included links to all the guides and manuals I used, in case you want to try this project yourself.
If you’re thinking about switching your Legion Go S to Steam OS, I can confidently say it’s worth the effort. The performance is impressive, the system is stable, and aside from a few compatibility limitations, it’s a fantastic setup for portable PC gaming.
References
LegionGoLife. (2025, May 23). How to install SteamOS on the Legion Go. LegionGoLife. Retrieved June 13, 2025, from https://legiongolife.com/how-to-install-steamos-on-the-legion-go/
NVIDIA. (n.d.). GeForce NOW. Retrieved June 13, 2025, from https://www.nvidia.com/en-us/geforce-now/
ROG Ally Life. (2025, May 23). How to install SteamOS on the ROG Ally & ROG Ally X. ROG Ally Life. Retrieved June 13, 2025, from https://rogallylife.com/2025/05/23/how-to-install-steamos-on-the-rog-ally/
Steam Support. (n.d.). SteamOS. Valve Corporation. Retrieved June 13, 2025, from https://help.steampowered.com/en/faqs/view/1B71-EDF2-EB6D-2BB3
Lenovo. (n.d.). Lenovo Legion Go S user guide. Retrieved June 13, 2025, from https://download.lenovo.com/consumer/mobiles_pub/lenovo_legion_go_s_ug_en.pdf
Lenovo. (n.d.). Legion Go S guides and manuals. Retrieved June 13, 2025, from https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/legion-series/legion-go-s-8apu1/document-userguide