Mega FLE X guide (Rockman 4)

ROM MAP
http://datacrystal.romhacking.net/wiki/Mega_Man_IV:ROM_map
-To change the values listed here, open MM4 in FCUEX and go to Debug > Hex Editor > View > ROM File. Then scroll down to the corresponding number for what you want to change. I believe the values are the same for Rockman 4.
-The number values used are different depending on how the game interprets that address, so you might have to intuitively figure out a good value or test it through trial and error. Stuff like weapon energy is usually pretty easy, 01 is 1 per use, 02 is 2 etc.
-Also, these are in hexadecimal, so "10" is actually "16", where 0A through 0F are 10 through 15. You get a handle on it eventually.

PATCHES
Use LunarIPS to patch your rom file with these for some game mechanics changes, if you want. Keep in mind that some players would rather have the game's original mechanics, warts and all. These are designed for Rockman 4.
-Allow slidejumps in water: http://www.geocities.jp/borokobo/zip/Rock4SlideJumpInWater.zip
-Fast Scrolling/Instant Health+Ammo Pickup: http://www.geocities.jp/borokobo/zip/Rock123456RecoverFade_090802.zip (use the mm4 one)
-Optimization Patch: http://www.geocities.jp/borokobo/zip/Rock4Optimization_v3.zip (Std reduces lag and sprite flicker, Exp does that but also adds quick weapon switching, faster scrolling and boss health fills, and instant health/ammo pickups).

MEGA FLE X
This is a brief rundown of how to use the editor. There might be a more comprehensive tutorial out there, but these are the basics of what I figured out.

RANDOM NOTES/ADVICE:
-Sometimes when scrolling through the screen editor, stuff will start looking corrupted or off. Usually it's still fine in the game, the editor is just showing the wrong tileset or palette because it sticks with the one that was last loaded from viewing a screen with a tile/palette change. Keep file backups just in case.
-Press F9 to test the level in emulator (it'll ask you to specify which one to use). Put savestates before screen transitions so you can quickly test things you've changed (if you save in a room and then change the room in the editor, the game might not update it correctly).
-F5 to save, F4 to revert, F3 to revert further. Be careful about accidentally pressing F4 if you haven't saved in a while. I've lost a lot of work to that.
-I know of two ways to crash the editor: Don't move the file out of the directory it's in while it's still open in the editor, and don't use the arrow buttons in the Enemy Editor to move an enemy past the screen boundary (00 or FF).
-You're going to break a lot of stuff. I repeat this a lot throughout the tutorial, but keep a lot of backups.
-Also, your first attempt at a hack won't be your best work, simply because the learning process takes a lot of trial and error. Don't be afraid to do a test hack first or even scrap something and start over because you think you can do it better after learning a lot.

PALETTE EDITOR: This lets you change the palettes used by each level, including animated backgrounds for MM3-5.
-Be careful with the Palette Animation Editor. It's easy to break something in MM4, particularly backgrounds in Bright.
-Most stages use multiple palettes to get a bigger range of colors, so some tiles won't look right when paired with the wrong palette. For example, trying to put quicksand in the underground section of Pharaoh will have it show up as blue/green, because the torches in the background use a different palette for that section. You can change which BG palette a scroll map is using in the screen editor (0-3 usually).
-You can also change Mega Man's default color and weapon colors in the Weapon Menu tab.

SBD EDITOR: This lets you draw the block currently selected in the TSA Editor directly into the level. It's useful for basically painting finer details into your level. Once you do, press "Convert to Normal Data" and the editor automatically creates new structures from what you drew, and cleans up any unused ones in the Structure Table. If you draw too many unique structures, you'll run out of space, so I try to use this sparingly.
-The SBD Editor doesn't update automatically, you have to click "Import (all screens)" to bring any changes into it.
-Sometimes it doesn't update graphics or palette information accurately either. Make sure the Screen Editor is on the same screen as the SBD Editor if so, or change to a different level and then change back.

TILE TABLE: Here's where you can redraw stage tiles, the smallest graphical unit in the game. Click the right arrow to bring the selected tile into the drawing window, and use the mouse to draw on it (available colors on the right). Click the left arrow to update the selected tile with your redrawn one. You can bring in tiles from other stages, and even rotate or mirror them.
-Sometimes you'll find square shaped tiles that aren't used by the level. This is available space to draw your own additional stuff. I've also erased tiles the levels use in the vanilla game that I didn't need.

TSA TABLE: TSA blocks are made up of 4 tiles, often repeated. You can change the makeup of existing TSA blocks by selecting a tile in the Tile Editor and right-clicking one of the 4 quadrants of the TSA block. You can also make new TSA blocks out of different tile combinations in spaces the game doesn't use (Tools > Clear Unused TSA Blocks (for level) if it looks full).
-Tiles by themselves are just graphics. You could make a wall TSA that's actually a background, or an invisible ladder, or spikes that are actually water, etc. I don't recommend the last two.
-Every TSA block is assigned a property, which appears in a list. Some only work in certain levels (like the Slippery tile, which is assigned only to Cossack 1 by default).
-The game sometimes uses a copy of background TSAs as walls in boss rooms or to replace doors. Be careful that you select the TSA with the right property when drawing backgrounds or whatever else.

STRUCTURE TABLE: Structures are made up for 4 TSA blocks. You can change the makeup of them by selecting a TSA block in the TSA table and right-clicking one of the 4 quadrants of the structure block. You can make new structure blocks in empty spaces at the end of the editor (to clear space, import all screens into the SBD Editor and Convert to Normal Data, which will remove anything not used by the level).
-If you run out of space, you'll have to find a structure in the level you don't need and try to eliminate all instances of it.
-What seems like duplicate structures are often only graphically identical. Make sure you're using a structure with a LadderTop TSA at the top of a long ladder, or you won't be able to climb all the way up it.

SCREEN EDITOR: Here's where you can rearrange structures by selecting one in the Structure Table and left-clicking squares. You can also right-click any square to select that structure in the table and left click to place it somewhere else. The Screen Editor also governs how screens scroll - be sure to save a lot of backups when learning this, because it's very easy to break a level and there's a lot of rules for it.
-Any stage in MM4 can have up to 16 scroll maps (0-F). A scroll map is from the start of a screen to the next time it scrolls, so for long horizontal sections it can be a large number of screens (I don't know the maximum).
-Scroll Type determines the direction a screen is entered (and sometimes exited). Scroll through the existing stages to learn how these behave if you want to reorganize a stage.
-Screen Length is the number of screens in a scroll map. Set this to 0 if it's only one screen long, or a vertical section. A down scroll map that's 2 screens long will just be confusing later.
-BG Palette determines the palette used by the current scroll map. Scroll GFX Load changes the enemy graphics loaded for the current screen.
-Screen Preset will let you duplicate screen layouts in multiple screens in the level. This is useful if you want to do a longer horizontal section that repeats terrain but with different enemy placement, so you don't run out of available screen space (the boat section in Wave Man repeats 2 alternating screens 30+ times for example). I think 1F is the last available screen preset for any stage (so 32 unique screens per level).
-Alternate paths sometimes appear at the end of a level in the editor, like the secret Eddie room in Ring, the wire pit in Dive, or the alt path in Cossack 4. I don't know how the game knows where to load these, so they might not be easily moveable.
-Sometimes after the boss room you'll see what looks like a bunch of garbage screens. Sometimes these actually have a function. Preset 1A on Ring Man is how the Hippo miniboss graphic is loaded in, so don't mess with it.
-Set Midpoint sets the first checkpoint in the stage. Set Bosspoint sets the second checkpoint in the stage. The Bosspoint doesn't have to be in the boss corridor, you could give a stage 2 checkpoints instead. Midpoint has to be before Bosspoint though.

ENEMY EDITOR: Here's where you can move enemies, place new ones, and change their damage, weakness, and health properties. This is the most complex editor and the easiest one in the program to accidentally break something, so be cautious with it and always keep file backups.
-The info is on the bottom left. All numbers are in hexadecimal, so don't forget 10=16. Enemy # is the ID of the enemy in the level, and they're ordered sequentially. The editor should reorganize them automatically, but there's an option to change that (it causes some weird issues so I don't recommend it). Type will change the type of enemy. HP, X Position, and Y Position are obvious. Increasing the screen value will move the enemy to different screens without changing its spawn position.
-Only certain enemies can appear on the same screen together, because of how MM4 loads sprite sheets. You'll find a list of enemies using the current loaded sprite sheet on the right, but occasionally the game uses sheets that can support enemies that aren't actually listed. Sometimes enemies can appear together, but don't share a palette, so the game will get confused and switch between palettes as it loads them. You'll have to see what works well together by testing.
-Hovering over an enemy in the editor selects it, and clicking moves it around. If you have trouble selecting an enemy, you can click the arrow buttons on the Enemy ID list in the bottom left to cycle through enemies in the stage.
-Here's how you'll most likely break something with the editor: The game considers a lot of effects and functions as "enemies", and they appear in the editor here. You'll see Eff: 1A in the hippo rooms in Ring, which is the pillar platform effect. Bright uses a number of effects for dark sections or background palette changes (they use X and Y position to tell the game what they do, I believe). Always keep file backups if you plan to try to change any of these, and if you aren't sure what you're doing, don't try. Be diligent about backups, keeping track of what you changed, and testing stages, so you don't break something no one knows how to fix and only find out about it after completing 5 more stages.
-You can change enemy palettes by clicking the colors below the sheet, but keep in mind it affects everything on that sheet across the entire game.

DOOR EDITOR: Here you can change what screens doors appear on, what tiles are behind them when they open, and where on the screen they animate. I'm not familiar with how to use this for MM4 yet, and it wasn't supported for 6, so I wouldn't mess with the doors until you're sure you understand it.

MISCELLANEOUS: There's a few useful things in here that I haven't spent any time with yet. Backup before testing it out.