As you might guess from the name, this patch takes the SMW Scratch ROM patch and turns it up to 11. This patch erases ALL original level data (including exits) and repoints all pointers to blank data, including those for special levels such as the bonus game. This gives you a completely clean slate to work with and enables you to use most of banks 06 and 07 for freespace if you so choose. It does cause an incorrect checksum, but the ROM still works perfectly fine.
UPDATE (Erik): added an option to not nuke no Yoshi intros, changed to Asar format, added SA-1 support.
While the usefulness of this patch is debatable, it's definitely nice to have a better version of it. Not only does this update fix the crashing problem with No Yoshi level intros, it also makes the patch's code quite a bit easier to read.
Of course, it is worth repeating that this patch will completely destroy the original level data and overwrite all current data pointers, meaning it will also make the current level data inaccessible, even if it's not original. If you feel like you can use this patch, do not apply it to a ROM which has levels you might need.
During the moderation, I corrected the conditional operator for the if statements in the patch. It used a single equals sign as opposed to two, which is a deprecated Asar feature and not future-proof.