Hi, I think there is an issue with directory handling. We found this while accidentally opening a directory instead a file. This let yaffs crash: handle = yaffs_open(directory, oflag, 0755) yaffs_lseek(handle, (Y_LOFF_T)0, SEEK_SET); yaffs_close(obj->handle) when directory contains a directory name. Reason is that in yaffs_lseek the v member of yaffsfs_FileDes is touched: if (pos >= 0 && pos <= YAFFS_MAX_FILE_SIZE) fd->v.position = pos; Later when closing in yaffsfs_PutFileDes v is used again: yaffsfs_closedir_no_lock(fd->v.dir); I think there is a check missing in yaffs_lseek if the handle points to a directory. What do you think? Robert.