Wow... you have some serious issues man
I'd recommend having someone look over the components (resistors) around your NAND, and dumping it the hardware way...
Most likely one of them resistors is bad or not connected properly as XeLL shouoldn't print out that error in normal cases...
Having a dump you made previously is kinda pointless, it'll most likely not have any issues, however... seeing as you have this error i'd say it's a hardware fault with the resistors there changing the configuration for the nand... (it probably thinks it's 8mb and not 16mb as it should) that'd explain why the dashboard don't work but xell do...