nvflash Complete Reference: Commands, Flags & Version Guide

Version Overview

nvflash is NVIDIA's GPU firmware flash utility, distributed in command-line form for Windows (nvflash.exe) and Linux (nvflash binary). NVIDIA does not officially distribute nvflash for enthusiast use; it is obtained from community archives where AIB partners and NVIDIA employees have released builds tied to specific driver development cycles.

The version number format is a dotted quad (e.g., 5.820.0). The third component increments with each architecture generation; a version must meet or exceed the minimum required for the target GPU's generation. Using an insufficiently versioned nvflash against a newer GPU produces "No NVIDIA display adapter found" or a device detection error even when the card is correctly installed and the driver is loaded.

Command Reference

Information and Enumeration

# List all NVIDIA GPUs in the system with index, device ID, SubVendor ID, BIOS version
nvflash --list
nvflash -l

# Display current GPU's BIOS version, device ID, SubVendor ID without modifying
nvflash --version
nvflash -v

# Display detailed adapter information for adapter index 0
nvflash -i 0 --version

Saving (Backup)

# Save BIOS from the default (first) adapter
nvflash --save output.rom
nvflash -s output.rom

# Save from a specific adapter index (multi-GPU)
nvflash -i 1 --save gpu1.rom

# Save with verification (read back and compare)
nvflash --save output.rom --verify

Flashing

# Flash BIOS — same device ID and SubVendor ID (prompts for confirmation)
nvflash target.rom

# Flash BIOS — force (skip confirmation prompt)
nvflash -6 target.rom

# Flash to specific adapter index
nvflash -i 1 -6 target.rom

# Override SubVendor ID check (cross-flash between AIB variants)
nvflash -6 target.rom
# Note: -6 is the combined flag for SubVendor override + force flash

# Override SubVendor check only (still prompts for confirmation)
nvflash --overridesub target.rom

Protection and Access

# Disable BIOS write protection (required on some Windows configurations)
nvflash --protectoff

# Re-enable write protection after flash
nvflash --protecton

# Check current protection status
nvflash --getprotection

Verification

# Compare a ROM file against the installed BIOS without flashing
nvflash --compare target.rom

# Verify after flash by reading back and comparing
nvflash target.rom --verify

Flags Quick Reference

Linux Usage Notes

The Linux nvflash binary is functionally identical to the Windows executable. Key differences:

• Run as root or with sudo — direct device access requires root privileges in all modern Linux kernel configurations.
• Best run from a text console (TTY) with X11/Wayland stopped: sudo systemctl isolate multi-user.target before flashing.
• The Linux binary may require chmod +x nvflash after extraction.
• Some distributions' kernel configurations include additional security modules (AppArmor, SELinux) that may block nvflash's direct device access — boot with module in permissive mode if encountering unexplained permission errors.

Error Code Reference

Standard Flash Workflow

# Complete nvflash workflow — single GPU system, Pascal/Turing

# Step 1: Check GPU detection and note device/SubVendor IDs
nvflash --list

# Step 2: Save backup (MANDATORY)
nvflash --save original_bios.rom

# Step 3: Verify backup file size is correct (should be 256KB–2MB)
# On Windows: dir original_bios.rom
# On Linux: ls -lh original_bios.rom

# Step 4: (Optional) Compare new BIOS with current before flashing
nvflash --compare target_bios.rom

# Step 5: Flash
nvflash -6 target_bios.rom

# Step 6: Reboot
# Step 7: Verify new BIOS version in GPU-Z