This simple patch modifies the intangibility timer ($154C) after kicking shells and p-switches to shorten their timer (or simply zeroes them out to instantly expire it) when they hit a wall. This makes it so you don't need a 2-block space between the player and the wall in order to shelljump.
While some people may prefer the vanilla physics of shells bouncing off of walls, I'm sure that some others may find this patch to be useful if they're designing a hack with it in mind. It works as intended and has it definitely has some purpose, so it's accepted. Take note that midairs are NOT affected by this patch, since this only modifies the timer after the shell hits a wall. At that point, it's no longer a midair.
Added the lorom and sa-1 tags upon moderation, along with renaming the patch title slightly.
which that have a problem that the player can easily accidentally get hit by the shell before the shell leaves the player or if the player is moving towards them a few frames after kicking. I initally tested with these