The disclosure describes a method for securing the trustworthiness of an electronic device. At least first and second check-up data are stored in the electronic device. In the method, a first step of a boot program is executed. In the first boot step, the trustworthiness of the first check-up data is examined, wherein if the check-up shows that the first check-up data is trusted, the second check-up data related to the second boot step is examined to confirm the trustworthiness of the second boot step. If the check-up shows that the second check-up data related to the second boot step is trusted, the second boot step is executed after said first boot step.