No, I left the NAND driver built-in (not as module), as it comes after applying the kirkwood_defconfig. Of course, assuming that the driver is the one I think: "NAND Flash support for Marvell Orion SoC" (MTD_NAND_ORION).
Anyway, it seems there it not much interest in this specific kernel (at least yet), so I went back to 2.6.30-rc1 and I applied by hand the patch for SD cards that is mentioned in other threads (the one that avoids the high speed). This way I got a kernel that works with the NAND and all my SD cards. Then I compiled the bluetooth drivers (my original goal) as modules and everything worked like a charm. Now I am struggling with Java support for Bluetooth in the plug, but this is a different story...