The team behind the x360glitchip RGH-chip now also comes with a NAND-flasher for the 360:
It's done, the x360 SpiFlasher is available. This one will let you dump and flash your xbox 360 Nand easily.

Designed for both final users (who will install it definitly in their xbox) and technical users (who will use it several times on several xbox), it will cover all your needs.

Official Site: