in file:
src/apps/http/makefsdata/makefsdata.c:728

  src_offset = 0;
  for (offset = hdr_len; ; offset += len) {
    unsigned short chksum;
    const void *data = (const void *)&file_data[src_offset];
    len = LWIP_MIN(chunk_size, (int)file_size - src_offset);
    if (len == 0) {
      break;
    }
    chksum = ~inet_chksum(data, (u16_t)len);
    /* add checksum for data */
    fprintf(struct_file, "{%d, 0x%04x, %"SZT_F"}," NEWLINE, offset, chksum, len);
    i++;
  }

loop condition is wrong. src_offset never changed and as result len never reach zero.

I think right condition will be like that:

   for (offset = hdr_len; ; src_offset += len) {

8 years old BUG....