Methods for authenticating firmware in a computing device include partitioning functions critical to the intended role of the computing device so that, upon successful authentication of the firmware, all functions of the device are made operational. Otherwise, the computing device behaves in a diagnostic mode of operation to assist users in troubleshooting to eventually authenticate firmware. At least first and second sets of firmware are loaded at various times into a controller of the computing device with the first set occurring without verification of trustworthiness, while the second set occurs upon authentication of the first. The second is used to authenticate a remainder set of firmware. Particular computing devices contemplate laser printers, mobile phones, PDA's, gaming consoles, etc. Firmware downloads, error messaging, hash comparisons, signature table construction, page-in techniques, computer program products, and particular computing arrangements are other noteworthy features, to name a few.