1. A method of upgrading system capability of a communications network, the method comprising: initiating a transfer of at least one first set of system capability instructions from a first memory to a target processor; determining whether the at least one first set of system capability instructions is valid prior to completing the transfer of the at least one first set of system capability instructions; wherein determining whether the at least one first set of system capability instructions is valid comprises determining whether a header line of a first frame transferred from the first memory to the target processor is valid and the first frame transferred from the first memory to the target processor is a frame that was loaded last onto the first memory; if the at least one first set of system capability instructions is determined to be valid, completing the transfer of the at least one first set of system capability instructions to the target processor; and if the at least one first set of system capability instructions is not valid: ceasing the transfer of the at least one first set of system capability instructions from the first memory to the target processor; and transferring at least one second set of system capability instructions from a second memory to the target processor.