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Remove legacy ROMs

Difficulty: Risk: Reversibility: ✓ Total

This guide describes a basic and reversible procedure to resolve boot issues caused by incorrect CSM / Option ROM (Legacy) configuration on Lenovo ThinkCentre M910x systems.

Scope

  • Models: M910x
  • Risk level: Low
  • Does not require opening the chassis
  • Requires access to BIOS (Advanced menu must be unlocked)

Problem Description

When the Storage option is set to Legacy mode (CSM / Option ROM enabled), the system may:

  • Fail to boot the operating system
  • Remain on a black screen
  • Fail to properly detect the boot drive

It has been verified that the system boots correctly when Storage is configured in UEFI mode.

Quick Steps

  1. Fully power off the system.
  2. Power it on and repeatedly press F1 to enter BIOS.
  3. Access the Advanced menu (must be unlocked).
  4. Go to CSM Configuration.
  5. Change the Storage option from Legacy to UEFI.
  6. Save changes with F10 and reboot the system.

Exact BIOS Path

Advanced → CSM Configuration → Storage → UEFI

Technical Notes

  • Legacy mode forces the system to load traditional Option ROM firmware.
  • UEFI mode uses modern drivers compatible with current operating systems.
  • The change is fully reversible.
  • If set back to Legacy, the system may fail to boot again.