+ nand erase off|partition size
+ nand erase clean [off|partition size]
+ Erase `size' bytes starting at offset `off'. Alternatively partition
+ name can be specified, in this case size will be eventually limited
+ to not exceed partition size (this behaviour applies also to read
+ and write commands). Only complete erase blocks can be erased.
+
+ If `erase' is specified without an offset or size, the entire flash
+ is erased. If `erase' is specified with partition but without an
+ size, the entire partition is erased.