A technique verifies a that a module is from an approved vendor. The technique involves obtaining vendor data and a first magic code from a module (e.g., a small form factor pluggable component), and generating a second magic code based on the vendor data. The technique further involves outputting (i) a magic code valid signal when the second magic code matches the first magic code, and (ii) a magic code invalid signal when the second magic code does not match the first magic code. Operation of a computerized device having the module can be based on the valid and invalid signals (e.g., a voltage level, a bit that is set or cleared, a value in a register, etc.). For example, a supplier of the electronic device can configure software running on the computerized device to disable the module if the first and second magic codes do not match.