Are you 100% sure on that? Maybe nand is fine, but I've seen CoolRunners flashing the green led with problems at the nand. For you to understand it properly. XeLL is a bootloader, it is located at 0x00 - 0x50 (the first 50 blocks of the nand) so if you reach XeLL, the console is "booting" right? But you can have the rest of the nand empty, it doesn't check it, that's why I suggest to try to boot retail nand, because at retail it does check the nand, that's basically what the Hypervisor exploit does, bypass those checks.but since its flashing green, nand is fine, must be something else stopping it.; but probably have to send it to be fixed,