In the world of Linux-based satellite receivers (such as the Dreambox, GigaBlue, or Vu+ series), the operating system is not static. It is stored on a flash memory chip and can be replaced, upgraded, or "flashed" with different images (software versions).
Do you have a you're trying to flash, or are you running into a particular error during the download? tuxbox-neutrino/bootloader-uboot-cst - GitHub
Never disconnect the power or the cable while the "flashing" process is in progress, as this is the most common cause of "bricked" hardware.