You will see a simple menu:
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PC CMOS Cleaner v2.0 - USB Edition
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[1] Auto Detect & Reset CMOS
[2] Manual Port Scan (0x70-0x7F)
[3] Clear Passwords Only (Keep Settings)
[4] Full Checksum Corruption (Factory Reset)
PC CMOS Cleaner 2.0 is a double-edged sword.
Important: Many modern systems (especially corporate Dell Latitude/HP EliteBook post-2020) store passwords in a discrete EEPROM (like the MX25L6406E flash chip). The USB boot method will not work on these. You will need a hardware programmer and a SOIC clip.
Cause: CMOS reset corrupted the checksum, but the BIOS is locked into a "recovery mode." Solution: Remove power, remove CMOS battery for 30 minutes, then boot once without the battery. pc cmos cleaner 2.0 usb boot
PC CMOS Cleaner 2.0 is a DOS-based utility used to decrypt and remove BIOS passwords. It is particularly useful for technicians repairing second-hand computers or users who have forgotten their BIOS access credentials.
Primary Function: It attempts to disable or erase the "CMOS" memory where the BIOS settings and passwords are stored, or to calculate the master password for specific BIOS manufacturers.
Supported Manufacturers: The tool historically supports major BIOS vendors including: PC CMOS Cleaner 2
Once your USB is prepared, follow this exact procedure:
| Hardware Method | USB CMOS Cleaner 2.0 | |----------------|----------------------| | Requires opening case | No tools, no disassembly | | Risk of static damage | Zero physical contact | | Can void warranty | Boot-only, reversible | | Ineffective on soldered batteries | Works regardless of battery |
PC CMOS Cleaner 2.0 is a freeware utility designed to reset CMOS (Complementary Metal-Oxide-Semiconductor) memory without physically opening the computer case or removing the motherboard battery. Lenovo ThinkPad T490).
Unlike basic CMOS reset tools that simply clear the date and time, version 2.0 specializes in debugging the I/O port (usually port 0x80 or 0x70/0x71) to overwrite BIOS checksums. This effectively:
Cause: Password stored in a security chip (TPM) or EEPROM separate from CMOS. Solution: Use a hardware SPI programmer (like CH341A) for direct EEPROM flashing. PC CMOS Cleaner 2.0 cannot reset TPM or non-volatile BIOS passwords on 2019+ laptops (e.g., Lenovo ThinkPad T490).