Lenovo Legion Go S: SteamOS Failed to Boot - Diagnosis

⚠️ SAFETY WARNING / FIRE RISK. This device contains lithium batteries. Improper puncturing or bending during disassembly can cause explosions or flames. The intervention requires precision and the assistance of a specialized technician is recommended. ReeFix provides this diagnosis EXCLUSIVELY for educational and informational purposes.

Why won't SteamOS boot on my Legion Go S anymore?

The failure of SteamOS (or other Linux distributions like Bazzite, Nobara) to boot in dual boot on your Lenovo Legion Go S is a common problem rooted in UEFI firmware and SSD management. Here are the most probable causes:

1. UEFI boot variables overwritten by Windows (65%)

   • Why: Often, after Windows updates or firmware updates distributed via Windows Update, the Microsoft system tends to reset the "Windows Boot Manager" as the primary boot option. This completely ignores the SteamOS entry, causing you to boot directly into Windows.
   • Key signs: The console turns on and immediately goes to Windows, without showing any operating system selection screen. SteamOS seems to have "disappeared."
   • Often happens when: important Windows updates are performed or specific manufacturer drivers (Lenovo) are installed via Windows Update.

2. Secure Boot re-enabled in BIOS (20%)

   • Why: Many Linux distributions do not have the digital signature keys approved by Microsoft for Secure Boot. If a BIOS update restores factory settings, Secure Boot reactivates, blocking SteamOS from booting because it is not recognized as "secure."
   • Key signs: On startup, you might see an error message like "Security Violation" or the system returns to the BIOS without loading Linux.
   • Typical user error: Not checking BIOS settings after a significant update or reset.

3. Logical corruption of the EFI partition or file system (10%)

   • Why: Sudden shutdowns or Windows' "Fast Startup" feature can leave the EFI partition in a "dirty" state. This prevents the Linux bootloader from correctly reading configuration files or kernel modules.
   • Key signs: The SteamOS bootloader attempts to start but gets stuck on a black screen, enters a recovery shell (e.g., grub rescue), or shows read errors.
   • Counter-example: If Windows starts normally and there have been no recent crashes or forced shutdowns, this cause is less likely.

4. Thermal or physical degradation of the NVMe SSD (5%)

   • Why: The M.2 2242 SSD of the Legion Go S, if subjected to prolonged thermal stress (e.g., long gaming sessions), can develop micro-corruptions in the data. This can compromise the EFI partition or SteamOS files.
   • Key signs: Random read/write errors, sudden freezes on both operating systems, or the BIOS does not detect the SSD at all.
   • Edge case: Intensive use of the device in hot environments or with poor ventilation can accelerate this type of degradation.

Can I repair it myself or do I need a technician?

Repairing these problems has a medium difficulty (⭐⭐⭐). If you are familiar with BIOS/UEFI and using the Linux terminal, you might attempt the repair yourself. Otherwise, a specialized technician is strongly recommended.

Quick checks (for expert users):

• BIOS/UEFI access: On power-up, try pressing Volume Up + Power. Look for "Boot" or "Security" sections.
• Secure Boot check: If you find the "Secure Boot" option, verify that it is set to "Disabled." Try disabling it if it is active.
• Boot order: In the "Boot Priority" or "Boot Order" section, check if there is an entry for SteamOS or a custom boot manager (e.g., rEFInd). If there is, try moving it to the top.

Tools needed (if you decide to intervene):

• Samsung Duo Type-C USB stick for Lenovo Legion Go S: Essential for creating a bootable recovery medium (Linux Live USB) and accessing the terminal.
• iFixit Pro Tech Toolkit precision screwdriver kit: Only necessary if you need to physically access the interior to replace the SSD.
• WD SN740 NVMe M.2 2242 SSD for Lenovo Legion Go S: Only if the diagnosis points to a hardware failure of the storage unit.

Safety notes: Any physical intervention requires the device to be unplugged from power and attention to lithium batteries. If you are unsure, do not open the device.

Output for technician (if you decide to take it in): "The Lenovo Legion Go S no longer boots SteamOS after a Windows/firmware update. The system boots directly into Windows or freezes. Verification of NVRAM variables (efibootmgr), Secure Boot status, and disabling Windows Fast Startup is required. Please check the integrity of the EFI partition and, if necessary, perform a SMART test on the NVMe SSD."

What are the estimated costs and is it worth repairing?

Costs vary significantly based on the cause and whether the intervention is DIY or professional.

• Software repair (bootloader, Secure Boot, Fast Startup):

  • Cost: Low. If you do it yourself, only the cost of the USB stick (approximately 10-25 euros).
  • Technician cost: Generally 40-80 euros for labor, as it does not require spare parts.
  • Is it worth repairing? Absolutely yes. This is the most probable cause, and repair is almost always cost-effective.

• NVMe SSD replacement:

  • Cost: Medium-High. The cost of a WD SN740 NVMe M.2 2242 SSD for Lenovo Legion Go S can range from 50 to 150 euros, plus technician labor (another 40-80 euros).
  • Is it worth repairing? In most cases, yes, replacing the SSD is cheaper than buying a new device.

Operational decision:

Given the high probability (85%) of a software problem related to the bootloader or Secure Boot, it is recommended to consult a specialized technician for restoring UEFI and system configurations. If you are an expert user, you can attempt quick BIOS checks and the use of a Live USB. SSD replacement is a remote option (5%) to be considered only after ruling out all software causes.

If you find that your WD SN740 is not detected in the BIOS or causes sudden blue screens, it could be a known firmware bug related to power saving mode. In these cases, an SSD firmware update or replacement definitively resolves the hardware recognition problem.