Here's what I did this time:
Open the ROM
Go to level 1C5
Insert Sprite 19
Save, ignoring the message
Open the OW Editor
Go to Level 140
Load the Boss Test Room, copy the background from Forest Fortress, and save
Go to event 0x29 (Red Switch Palace) at random
Place event tile 8E (Donut Secret 1 Tease) at the bottom of Vanilla Fortress waterfall
Place another below the Koopa Kid near Chocolate Island 1
Place two Yoshi's House tiles near said Koopa Kid, on the tiny outcrops
Change the Left Yoshi's House to Level 139, Event 77, Right on Normal Exit, "Enable Down" and "Save Prompt", and reveal on Event 28
Change Top Secret Area Message 1 to "In Heaven's stead, we smite clothing."
Change the name of level 112 to "Puppysmiles"
Connect levels 112 and 113 with path tile 23
Set level 139 as the teleport destination for the middle Koopa Kid
Make a manual backup
Reopen LM and the ROM
Replace level 139 with Chocolate Island 2 secret exit
Open the OW editor
Copy the island near Top Secret Area into the area below the Layer 1 Tilemaps
Copy the left half of the shipwreck tile into the top right of the Special World
Copy the Main OW into the bottom right of the Event Tiles
Install the new LM hack
Change Yoshi's House to Level 140 and event F9
Change the name of level 140 to "Scotch Tape"
Change level 1DB message 2 to "Super Mario Bros. 4 Yellow Illusion" with the special characters for all but the last two letters
Change the previously unset Yoshi's House to level 192, event CD, and to have the Midway Point be obtained
Set level 192 as the teleport destination for the first Koopa Kid
Change Level 192 to have the boss activate the secret exit
Disable the path fade effect
Open level 192
Open address 306F5
Move the entrance to the top of the slope
Test the ROM and attempt to enter a few levels
Everything works fine, but I can't move off level 140 even though directions are enabled.
Duplicate level 140 and restore te original 104
Make a shortcut pipe to Vanilla Dome 1
Save and test again
Basic code works perfectly fine as far as I can tell, no issues here.
The flags have issues, 192's 3up flag was set to 1 and the game ignores the starting settings, but that's about it. The directions even save properly, even though they can't be enabled from the beginning
Assembling gives no problem, however, I can no longer use pipes, which I was perfectly capable of doing before I inserted the patch. If anyone wants to try to figure this one out, feel free.
Looks like not installing the patch is the way to go, though...
Let's milk Sunny Milk. Then she'll have enough money to fund Sunny Milk Real Estate.
Everypony's digging with a shovel