In other news, I'm pretty sure I managed to increase room size.
Don't talk to Tom Nook after doing this, unless you're fully capping your house size. I have other notes in the post below, make sure to check them
BEFORE PLAYING WITH THIS, MAKE A SAVE BACKUP
So, for room size, the values that are safe to use are 02 (4 X 4),03 (6 X 6) and 04 (8 X 8). 01 shouldn't be used, as it means the room is not built.
Values
PLAYER ONE
Main room size : 0x57eb6
First floor size : 0x581b8
Basement size : 0x584ba
Right room size : 0x587bc
Left room size : 0x58abe
Back room size : 0x58dc0
PLAYER 2
0x590de - main room
0x593e0 - 1st floor
0x596e2 - basement
0x599e4 - right room
0x59ce6 - left room
0x59fe8 - back room
PLAYER 3
0x5a306 - main room
0x5a608 - 1st floor
0x5a90a - basement
0x5ac0c - right room
0x5af0e - left room
0x5b210 - back room
PLAYER 4
0x5b52e - main room
0x5b830 - 1st floor
0x5bb32 - basement
0x5be34 - right room
0x5c136 - left room
0x5c438 - back room
After you inject. Save and Quit the game, then reload. The modifications will be effective once you have reloaded. THIS IS WHY MAKING A BACKUP BEFORE IS IMPORTANT.
OTHER THINGS
Don't talk to Tom Nook after doing this, unless you're fully capping your house size. I have other notes in the post below, make sure to check them
BEFORE PLAYING WITH THIS, MAKE A SAVE BACKUP
So, for room size, the values that are safe to use are 02 (4 X 4),03 (6 X 6) and 04 (8 X 8). 01 shouldn't be used, as it means the room is not built.
Values
PLAYER ONE
Main room size : 0x57eb6
First floor size : 0x581b8
Basement size : 0x584ba
Right room size : 0x587bc
Left room size : 0x58abe
Back room size : 0x58dc0
PLAYER 2
0x590de - main room
0x593e0 - 1st floor
0x596e2 - basement
0x599e4 - right room
0x59ce6 - left room
0x59fe8 - back room
PLAYER 3
0x5a306 - main room
0x5a608 - 1st floor
0x5a90a - basement
0x5ac0c - right room
0x5af0e - left room
0x5b210 - back room
PLAYER 4
0x5b52e - main room
0x5b830 - 1st floor
0x5bb32 - basement
0x5be34 - right room
0x5c136 - left room
0x5c438 - back room
After you inject. Save and Quit the game, then reload. The modifications will be effective once you have reloaded. THIS IS WHY MAKING A BACKUP BEFORE IS IMPORTANT.
OTHER THINGS
ALRIGHT. Full results on room size.
NOTES
MAKE A BACKUP BEFORE EDITING. THIS IS SERIOUS. And if you already made a backup, MAKE ANOTHER. I have a backup of my town, I have a backup of my .bin file and I have a backup on my powersaves. THIS IS HOW IMPORTANT BACKUPS ARE.
First, don't ask for expansions with Tom Nook when you're manually editing your house. You'll end up wasting bells and we don't want that.
If you expand all of your rooms to max size, Nook will acknowledge it. You just won't get the little Raccoon dance. Lyle will also offer you the theme challenge the day after.
Your house exterior size will NOT CHANGE if you only change your room sizes. Therefore, even if you have all of your rooms at 04, you'll have the same exterior as when you originally started. You'll have to manually edit it to the size you want.
Same with house shape. If you want a zen castle, castle or modern house, you'll have to edit it yourself.
You CAN change the wallpaper and flooring of each room. By default, it's Common Flooring/Common Wall, but you can modify them with HxD with no problem. The bytes for the wallpaper/flooring are near the end of each room.
Furniture cannot be modified. We saw this when people were importing dream towns, and it's still the case here. No cookies.