RCW is stored in beginning of flash.
In Linux, you could use mtd_debug(from package mtd-utils) to read/write flash sectors as the following.
./mtd_debug read <device><offset> <dest-filename> <len>
./mtd_debug write <device><offset> <source-filename> [len]
./mtd_debug erase <device><offset> <len>
# mtd_debug erase /dev/mtd1 0x1000000 0x100000