Navi Customizer

The Navi Customizer (ナビカスタマイザー), NaviCust for short, is a NetNavi customization program built by Yuichiro Hikari. It was made for the PET models Plug-in PET, Advanced PET, Progress PET, and Link PET. In MegaMan Battle Network 3, if you used a program that the current Style did not support and rebooted MegaMan.EXE, you'd get an error, MegaMan would not be able to boot up, unless remedied with an Extra Code. In the 4th, 5th, and 6th game, however the errors disappeared due to MegaMan's overload to destroy Alpha. In doing so, he nearly killed him, but when Lan gives Yuichiro Tadashi Hikari's letter, MegaMan.EXE is back from Alpha's body. However, his letter removed the Style Change. So, Double Soul was made as a suitable replacement.

The Navi Customizer consists of a set area, and a Command Line running through the center of the area. Through all of its incarnations, it has three basic rules:
 * Solid programs must be placed with at least one block on the Command Line.
 * Textured programs must be placed OFF the Command Line.
 * No two programs of the same color can touch each other.

Breaking any of these rules will result in bugs happening to MegaMan, and each bug has different effects depending on the part(s) that violate the rules. All bugs can be omitted by the NaviCust program BugStop, however, which allows all rules to be broken.

Each NaviCust piece is a combination of blocks, and is either completely solid or completely textured. If the player possesses the Spin item of a piece's color, he is able to rotate all pieces of the same color with the L or R buttons - a valuable asset when it comes to maximizing the use of the NaviCust's limited space.

The NaviCust is always at a tiny 4x4 area the moment you receive it. To expand it, you need to find "ExpMemory" items, which will boost the space to a 5x4, and eventually a 5x5 area, allowing for maximal programs to be installed.

The NaviCust is always introduced with the Undershirt, Attack+1, and Speed+1 programs.

Extra Codes
In MegaMan Battle Network 3, different Styles are compatible with different NaviCust program colours. If any of the programs are of an incompatible color, the NaviCust will bring up an error, and MegaMan will not be able to boot up, unless the player can remedy this using a ModCode (A.K.A. Extra Code).

To use the Extra Code, press Select in the NaviCust when the system reports an error or says "OK!". The screen will bring up a series of alphabets and numbers. By inputting the correct sequence, Lan can remedy the error and allow MegaMan to boot up. If no incompatibility error is present, the Extra Code can be input to give MegaMan extra abilities. Be warned that some abilities have side effects.

Compression Codes
Programs can be reduced by a few squares by inputting a Compression Code. Doing so will shrink it, allowing for more programs to be inserted. Each program has its own unique compression code in each game. In MegaMan Battle Network 3, to input the compression code, highlight the program that's going to be compressed, hold select, and input the commands. In MegaMan Battle Network 5 and 6, highlight the program, hold right, and input the commands.

Other Rules
In MegaMan Battle Network 4 onwards, the color compatibilities have been removed. Instead, MegaMan can now equip parts of any color, as long as he does not equip more than four different colours at the same time. Bugs will ensue if this rule is broken, too.

In MegaMan Battle Network 6, parts can now be placed OFF the Navi Customizer's main area, on the condition that at least one block of the part is left in the main area. Also, regardless of whether or not a block is on the main memory map, no blocks can be placed on the outside corners of the map (i.e. off-map areas only extend off the main map and do not allow corners outside of the map). This has resulted in the total space available being almost doubled. The Command Line is also capable of reading "hidden" parts, too, as long as they're aligned with the main Command Line. However, placing parts off the main area will, once again, result in bugs.