A long while back (we're talking 2018), I put together a little ZIP of modding tools for GH2 I still found useful so other people wouldn't have to dig around for copies. A lot's changed in the toolkit since 2018, so putting this on its own page and cleaning some things up was in order.

Goes without saying that a lot of these are fairly advanced modding tools without a lot of documentation to them. Some are outright command line tools, so if you don't know how to use a command line, you really should learn that first. (My dtab tutorial is a good place to start because it's such a simple, well-documented tool.) Beyond that, check in my tutorials section or ask in MiloHax. That's all I have to say on that.

I've got a much cleaner big bundle of tools (it's not just my GH2 folder zipped up anymore!) and also individual downloads if you only need one part of it. I'm not including any still-maintained tools in the pack—and that includes some big ones. I'd much rather people go and download it from the people who made it, let them give them kudos for making the damn thing, and always be sure they're getting the latest version rather than one I might not ever update. I'll list them first:

Still-maintained modding tools

Onyx Music Game Toolkit
This is the big one. Onyx used to just be for automating Rock Band modding, but as of late, Onyxite has been adding support for converting between a bunch of console rhythm games (with thoughts for adding more!), and it's basically become the tool people use to get RB/CH charts in GH2 in particular. It's hard to describe because it's so massive, but for GH2, the big thing is its batch importer. You just give it your ARK's HDR and it'll toss 70 charts into GH2 in one go, including drums and an author string if you're using Deluxe 2.0 as your base.
dtab
The other majorly useful Onyxite tool. This one converts and encrypt/decrypts between all of the known DTA and DTB versions from GH1 through Rock Band 3.
Mackiloha
From PikminGuts92 (somebody that we used to know 😔), this is the go-to tool for unpacking GH/RB ARKs and Milos (though support for unpacking Milos other than ones for GH2 is spotty). Seriously, ArkHelper will take an ARK down to files on your hard drive, and if you put the dtab executable in the same folder as ArkHelper (the only reason I put dtab before this one in the list), it'll even handle converting and performing crypts on the DTBs. Throw a new song into the songs folder, edit a script, run a batch file. New ARK. Way too convenient.
Samplitude
One more Onyxite tool. I probably shouldn't even be including this because it's only relevant to like two people, but I've gotten a lot of use out of it. Samplitude tries to generate stems from the chopped up song samples in the FreQuency and Amplitude game files. These games have pretty massively underrated soundtracks, and I've been mining them for GH2 customs for a little while now. (Samplitude is also how I put together my FreQuency soundtrack rip.) FreQuency support is a little spotty (you might encounter missing samples or pitch weirdness), Amplitude support is basically perfect.

marf's mirrored modding tools

Now we get to the meat of this page! Some of these are explicitly for modding GH, while others are used for either building disc images or opening disc images or DLC packages. They're all things I've needed to use in the course of trying to work on GH2, though.

If you just want the entire lot, here's a 7z. If you're looking for individual downloads, wanna browse, or want the two-sentence recap on what something's good for, keep reading:

Apache2 and Apache3
These are essentially identical IML-to-ISO solutions (IML being Sony's proprietary disc layout format—see CD/DVD Generator below). Apache3 is my usual, but sometimes, it throws up really nasty errors, so Apache2 is included as a backup. I believe these also can edit disc images directly, but I don't use them for that.
ArchiveExplorer
This would be my go-to swiss army knife solution for opening game archives, except that it only reads them, it can't edit them. Still, it works on most of the obscure ones, including FreQuency (which we still don't have a tool that can write ARKs for, grr) and the Amplitude OPM demo, which differs from final for some reason.
ArkTool
Old-school tool for adding and deleting files from ARKs. I know it works with GH1 up through RB2; anything else is a maybe, and anything really beyond that (like HDRless ARKs) is a no. Also included are some tools for encrypting and decrypting songs (really only the on-disc Rock Band 1 songs, I couldn't get even RB1DLC decrypted properly with it) and DTBs.
CD/DVD Generator 2.00
Official Sony kit time, yay! I mentioned IML files up there. The general gist is that, if you just make a disc image with ImgBurn or Nero, you likely won't get the necessary "official" Sony data that'll let you run burned discs on TEST PS2s and such. Ergo, you should use this for making ISOs. CD/DVD Generator is the tool you use to make your disc image layout, and then Apache is the tool you use to turn it into an ISO. Like I said, this is stuff Sony devs actually used back in the day, which is pretty cool.
C3 CON Tools v4.0.1
Wait a moment marf! I hear you say. This is for Rock Band! Yes it is. This is a big toolkit for manipulating and editing RB CON (a type of 360 package used for game saves, usually, though RB delivers DLC in CON files as well) files usually for customs purposes. Some of it is also useful for GH2 folks (like midishrink.exe).
Why am I mirroring this specific release? It's the last one that can decrypt RBDLC with the help of separate auth files. No, the auth files are not included because I'm not looking for a fight, but if you find them and drop them in the /bin/ folder, it will unlock that functionality. Fuji, Nemo, babes—be more careful with that stuff next time.
chart2midi_beta
This is a Java program for converting the plain text chart format to MIDI. The big advantage over the old Chart2Mid2Chart is that thing one will also import various notes in various tracks for animation purposes (Enhanced Guitar/Bass is used for fretmapping, Drums is used both for the on-stage drummer and the practice mode click). Thus, it's very possible to use this and FeedBack to create a nearly fully-featured GH2 chart without ever touching a MIDI editor.
DTB Editor (encrypted and unencrypted)
Two-fer. These are two versions of the classic, clunky, awful DTB Editor that people had to suffer through using back in the glory days of GH2. I very rarely use them anymore, but their sole useful trait these days is that the "line numbers" you get during a crash while playing GH1/2/80s are actually the node numbers in the DTB Editor. This lets you see exactly where in the script GH ate shit. As I said, there's two versions in here, one for encrypted DTBs and one for unencrypted DTBs, so if it won't open in one, try the other.
FeedBack
The classic (and in some cases infamous) charting program! I still think this one's pretty user-friendly and tailored to GH2, though I really don't recommend using it for tempomapping. In fact, some people will tell you to just plain use Moonscraper. I'm not one of those people (Moonscraper never quite felt right to me), but I do use it to sync a chart before I take it back into FeedBack to actually chart it. So, uh, yeah, I'd say it still has some value.
ghtool
A highly obscure and rather clunky Java applet for converting GH1 MIDIs to GH2 format with animations and such intact. This one needs some more investigation before I can recommend it. Last time I tried it, it seemed to be putting out broken MIDIs. Still, good starting point, so it sticks around.
RockLib
A suite of code/command line tools someone used for converting ARKs, MIDIs, and VGS files! This one went unused for the longest time because it's not very good. In fact, in testing for this page, I found RockMidi actually chokes on MIDIs that have extraneous TRIGGERS pitches authored, like I happen to have! What keeps this from the obsolete pile is RockAudio, which I still use very regularly for generating VGS files at arbitrary sample rates. If you're doing DIY (non-Onyx) customs, use RockAudio to generate VGS files.
WxPirs
Not strictly for GH purposes, but if you've stumbled upon rips of the GH2 360 DLC, this will open those packages up. It technically will also open Rock Band CONs, but I've encountered really bizarre MOGG errors (like random skipping and stuttering) after extracting with this. Use C3 CON Tools for ripping those files.
Xbox Backup Creator
And the equivalent ripping tool for GH2 360 on-disc! You can't just rip the ARK and HDR off a copy of GH2 360 with Windows Explorer, the files don't show up. Use this instead. (If you're trying to rip files from other Xbox 360 games, this will do as well, of course. jnack recommends XDVDMulleter as an alternative to ripping files from ISOs, but that's much easier to find from less sketchy sites.)

Obsolete tools

Yeah, these too. These range from good tools that are now out of date and have uncomfortable quirks and sharp edges the better tools don't to probably Guitar Wizard-level useless garbage. (I can't say. Some of these, I've never used.) Nevertheless, they're here for posterity.

No individual links or descriptions to discourage people actually using these (I promise you, as someone who mods these games regularly, you don't need any of these), but here's a list of what's in it:

  • ARK Expander
  • Chart2Mid2Chart
  • GH360
  • GH2MakerXbox
  • GH2 Image Converter
  • GH2 Name Editor
  • MiloExplorer
  • PSSdown
  • PSSInject
  • VGS Splitter