Firmware is the "built-in" software that control many of the devices (routers, DVRs,etc). This usually stays the same, but when neceesary updates happen, this can be updated by users. Sometimes, bug fixes require firmware updates and the update can improve service in some way.
Software for fios related hardware can be found here: Fios Firmware
Written by FiosFaq
Last updated on 09.17.06