Patch Cards in Mega Man Battle Network 6
From The Rockman EXE Zone Wiki
Using the e-Reader+, both versions of Rockman EXE 6 can scan e-Reader cards to further customize their MegaMan, as well as other features. Unlike in the previous two games, the data of the e-Reader cards were completely erased from the games, meaning there is no way to access them.
Information
Card e-Reader for Rockman EXE 6 come in 3 categories: Mod Cards, Item Cards, and Rare Chip Distribution Cards following in EXE 5's footsteps. All three types were distributed via Booster Packs with two parts, various EXE merchandise such as Guides and unique Japanese exclusive events.
Mods Cards
Mod Cards can be used to enhance your MegaMan with Abilities not possible normally. EXE 5 Introduced an MB system, which is kept for EXE 6 and works exactly in the same fashion.
Each card has a certain MB value, with MegaMan having a storage limit of 80 MB. Cards with higher MB generally have better Abilities. Individual cards can be turned on or off when needed, but this does not lower their MB use. This means that previous cards must be deleted when scanning new mod cards. All ModCard effects take place after NaviCust changes.