Also re: file write limit – the write limit occurs when the file is repeatedly opened and closed in a short period of time and not strictly when the write() function is called repeatedly (that is, it occurs when the file is repeatedly written to long-term storage and not when the file is modified in RAM). The write limit can be avoided by keeping the file open while you do reading/writing and only closing it once you're completely done accessing it.
Not sure what went wrong but you're right: the download code is X31M2MNDNE.
I also updated it again. The parallax-scroller now works seamlessly in both vertical and/or horizontal direction.
As kind of an extension of this, I made a system for serializing special sprites. They are just sprites, but with just a little extra handling.
They can't also have sprites as attributes though.
ID NX2D62FDN5