Mobile electronic devices and related methods to achieve an enhanced security level are disclosed. A security module is deeply embedded in a non-open companion chip of the mobile device, wherein the companion chip controls vital functions of the mobile device. Any security technology can be provided by the security module. The security module can, in case of a security violation, disable all vital functions of the companion chip without requiring communicating to other components of the mobile device. The vital functions deployed in the companion chip comprise e.g. system power management or audio functions.