Abstract: A wireless router receives a firmware update from a remote server, and destructively overwrites router firmware in flash memory in a chunk-wise manner, and then writes a kernel memory before going live with upgraded firmware. Some routers authenticate the firmware image. In some cases, image chunks are re-ordered into an executable order after receipt and before finishing their final arrangement in the flash memory. In some routers, a maximum firmware image size is at least two chunk sizes smaller than the flash memory storage capacity. Some routers remap ROM to RAM memory. Some decompress data from flash into a RAM. Some save text file configuration settings in flash before rebooting. Some detect a user's inactive billing status and redirect a web browser to a billing activation page.