cat the script, it's a wrapper (with some added things I don't care about so didn't read ) for the flasher binary. NOLO (the bootloader) does rootfs flashing, that's why you get a green bar indicating progress, flasher-3.5 simply sends the image, and NOLO writes it to /dev/mtd5 (don't write to this directly, you'll cause problems!). Flashing anything other than the kernel will return an "Unsupported in current mode"-ish error.