first suppose that you use yaffs inband mode ;
yaffs2_CheckpointFindNextCheckpointBlock get a buffer for read , the buffer 's content maybe
YAFFS_SEQUENCE_CHECKPOINT_DATA, but the block is a bad block , so the buffer 's content
donot changed after read, so yaffs2_CheckpointFindNextCheckpointBlock found a "checkpoint block";
I think the yaffs2_CheckpointFindNextCheckpointBlock should add bad block detect;