Bypassing an EFI lock on a device you do not own is illegal (Theft, Computer Fraud laws). This information is provided for security research, data recovery on e-waste, or recovering your own forgotten password. Write-Up: Removing EFI (UEFI/BIOS) Passcode Lock 1. Introduction The EFI (Extensible Firmware Interface) password, often called a BIOS password, is stored on a motherboard’s SPI Flash EEPROM chip. Unlike a OS password, it activates before the bootloader, preventing OS selection, boot device changes, or even full POST (Power-On Self-Test).

Example using xxd :

| Method | Difficulty | Tools Required | Success Rate | |--------|------------|----------------|---------------| | Default/Backdoor Codes | Easy | Serial number, Calculator | Low (old laptops) | | CMOS Battery Drain | Easy | Screwdriver | Very Low (modern NVRAM) | | SPI Flash Reprogramming | High | CH341A, SOIC clip, soldering iron | High (Universal) | | PS/2 Keyboard Interrupt | Medium | PS/2 keyboard | Legacy systems only | Method 1: Backdoor / Manufacturer Codes (Legacy systems) Principle: Older laptops (pre-2015) had hash-based master passwords.