You might find a version of Unlock Tool from 2021 with a leaked license file.
Open the device system for custom ROMs. The Truth About "Free Activation" Unlock Tool Free Activation
If you absolutely cannot pay, don't use a cracked version of Unlock Tool. Instead, look for that specialize in specific brands: Samsung: Look for SamFw Tool (often has free FRP features). Xiaomi: Use official MiFlash tools for authorized flashing. You might find a version of Unlock Tool
“Unlock Tool Free Activation” is predominantly a social engineering vector, not a functional solution. Users trade security for perceived savings, receiving neither safety nor lasting value. Future work should explore legal, low-cost licensing models that undercut the malware economy’s supply chain. Unlock Tool Free Activation