Missable content

This page lists items and content in the series which can be permanently missed, or become more difficult to obtain, if not obtained by a certain point in the game.

Mega Man Battle Network 4

Viruses

For most viruses, lower versions can be encountered even on the highest difficulty (Continue 3+). However, there are a few viruses that only appear on a specific difficulty. As a result, this may lock you out of obtaining certain chip codes, which can otherwise only be obtained (very rarely) from the Chip Trader.

Difficulty	Virus	Missable chip codes	Alternative ways to get
Game 1 only	GaiaEX	BigHamr1 R	Can be obtained from Chip Trader.
	CirKill	-	All codes can be obtained from CirKillEX.
	BomBoy	-	All codes can be obtained from BomBoyEX.
	WindBox	-	All codes can be obtained from WindBox2 and WindBox3.
	VacuumFan	-	All codes can be obtained from VacuumFan2 and VacuumFan3.
Game 2 only	Mettaur2EX	Guard2 *	Can technically be obtained from Chip Trader, but only through a redraw, so the odds are nigh impossible.
	SillyEX	-	All codes can be obtained from Silly.
	Gaia+EX	BigHamr2 W	Can be obtained from Chip Trader.
	KilburEX	SidBmbo2 H	Can be obtained from Chip Trader.
	Webby	WhitWeb2 E WhitWeb2 Y	Can be obtained from Chip Trader. Also, WhitWeb2 * can be obtained from WebbyEX.
	CirCrush	-	All codes can be obtained from CirCrushEX.
	MilkoEX	-	All codes can be obtained from Milko.
	WindBox2	-	All codes can be obtained from WindBox3.
	VacuumFan2	-	All codes can be obtained from VacuumFan3.