cOz released Rawflash v2, which allows you to flash your NAND from Xell '2Stages' (RGH Xell):

Let's you flash full raw images (16 or 64MB) to your NAND. Started, as usual, via XeLL.

NOTE: It doesnt have Bad Block Handling!

place "nandflash.bin" on the root of a usb device
start 2stage xell and shut off when prompted (replug power if you changed SMC)
- by default it checks blocks before writing, and will NOT overwrite or erase any block with ecc/other issues (perfect for fbbuild images with auto remaps)
small change to libxenon was required to silence non-error messages
tested on falcon, trinity and jasper 256

Download Rawflash v2
Source- LibXenon.org - Index