The present invention is related to an electronics device, such as a modem, having an interface operable with a complete protocol stack code in normal operation, and comprising a non-volatile memory, such as a flash memory containing a code for booting said device. The device is characterized in that software of said device is upgradable during a booting operation of said device via said interface, wherein said boot code comprises a lightweight protocol stack code for said interface, said lightweight protocol stack comprising a subset of the layers of the complete protocol stack.