This patch works similar to Kaijyuu's Overworld Event Restore Patch, but instead of giving you 16 KB of free RAM at $7F0000, it gives you 16 KB of free RAM at $7F4000 inside levels by forcing the game to reload its Overworld Layer 2 tilemap date on each level -> OW transition. To my knowledge, this hasn't been done before (either that or Google is seriously bad at finding any patches doing it). This is quite surprising since it really only required a single JML. The only trade-off is that aforementioned transitions take slightly longer, but in my opinion, it's barely noticable at all.
The patch can also be configured to only reload the OW data when a "dirty" flag is set to a non-zero value. In that case, the transition is only longer when the data actually needs to be reloaded. Just take a look at freeconfig.cfg for details on each setting.
Requires up to 1 byte of free RAM, depending on wheter you want to use a dirty flag or not (default is no dirty flag).
Moderator's note: If you have any plans to use it, your folder should look like this to get the patch to work (ignore the LM folder), then double click asar and type this when it says you to type the patch's name: free_7F4000/free_7F4000.asm. (image)
It's a very simple & nice patch, freeing up RAM is always welcome!