A few months back Skill, administrator of Rare game hacking site rarewarecentral.com, released a copy of Banjo's Backpack. It is a tool aimed at editing the N64 version of the original Banjo Kazooie. It is still not that common to see editors for N64 games and even 3d games in general so this is quite the tool.
You would do well to consult the the general FAQ and The getting started guide.
It seems to favour the v1.0 NTSC Big endian (no intro and co favour byteswapped these days) version of the game so you may need a copy of tool64_v1.11 to get it in order. Those looking at the European side of things might find PacoChan's editor worth looking at though it is aimed at text instead.
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