alt_read_flash()

What is the error code? Have you tried writing a smaller value? is there a boundry that it appears to not write on? In all my use of it i write only block_size chunks at a time. Don't know if you have to do that or not, but all my code does. So, you would have to read the regions data structure, which

alt_flash_fd* fd;
int number_of_regions;
flash_region *regions;
    fd = alt_flash_open_dev(flashName);
    if (!fd)
        return -EACCES;
    retval = alt_get_flash_info(fd, &regions, &number_of_regions);
    if (retval) {
        alt_flash_close_dev(fd);
        return errno;
    }