Normally, at the time of manufacturing, security may be provided to a device being manufactured through the loading of an operating system that has been cryptographically signed. The present application discloses a "factory mode" for the device. The "factory mode" allows the device to execute untrusted operating system code, such as unsigned operating system code and operating system code that has been signed, but the certificate authority is not trusted. To support execution of untrusted operating system code in a secure manner, the device may be adapted to prevent data of predetermined type from being loaded on the device while the device is in the "factory mode". In contrast to the "factory mode", the secure mode of the device is referred to herein as a "product mode". There develops a need to manage, in a secure manner, transitions between the "product mode" and the "factory mode".