New USB-to-I2C bridges allow software to read the 24CXXX series EEPROM chips on the Delta PCB directly. The password is stored in clear text or weak XOR encryption in specific memory addresses (e.g., 0x1F0 to 0x1FF).

Before diving into software, we must understand the lock. Delta PLCs offer three primary levels of password protection:

Older unlock tools often fail against newer Delta firmware (versions 3.0+ for DVP, or the entire AS series). As Delta enhances its cybersecurity measures to prevent intellectual property theft, legacy brute-force tools become obsolete. Hence, the demand for “new” software is not a marketing gimmick—it is a technical necessity.

Before discussing the new software, we must understand why you are locked out.

Delta Electronics (now Delta Group) is one of the largest manufacturers of PLCs in Asia. Unlike Siemens or Allen-Bradley, Delta focuses on cost-effective, high-speed logic controllers. To protect intellectual property (the "ladder logic" code), Delta implemented three levels of password protection:

The problem? In the chaos of industrial turnover—retirements, layoffs, bankrupt OEMs—these passwords are rarely documented. OEMs often lock the PLC to prevent non-payment, but once the invoice is cleared, they forget to remove the lock.

You need new unlock software when:

By: Industrial Control Security Team
Last Updated: October 2024