Stupid Question Time— Modifying Code!

Bricksnbeatles

Bricksnbeatles

Member known well
Howdy friends. I have a question that’s probably pretty stupid, but here it goes.

There are two use-cases where I want to modify code for existing pedal projects. The first is the Parasit Studio 1985 guitar synth, which holds code on two Attiny85 chips. Pretty much, there’s a secret boot-up mode where it will play back a three-voice chiptune arrangement of the Super Mario theme using the pedal’s three synth voices— problem is, I’d much rather have it play a different tune since Mario isn’t really on-theme for me. Fredrik provides hex files for the Attiny chips. Is this something that’s possible to modify for a novice such as myself to learn, or is stuff pretty much indecipherable once it’s compiled(?) into hex?

This ties into my second case, which is the bypass controller chip for VFE projects. I have a lot of VFE boards, but I really don’t like the method of switching between latching and momentary bypass. Having them be two separate modes is really inconvenient, and I much prefer the nice hold-for-momentary method that most other builders, including PedalPCB use, which allows for both momentary and latching operation without having to configure the pedal for one mode or the other. This uses a PIC12F509 instead of an Attiny chip, though the implementation of that isn’t really something I have a grasp on. Again, is it possible/feasible/worthwhile trying to alter the hex code to allow for a more user-friendly bypass experience? Or is there another feasible option for executing this?

Anyway, I’ll be in the corner until I hear from y'all. Thanks.
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From overhearing CS faculty talk about it: you can use software tools to wind up with what you need in order to code your own paraphrased version of the code. A recent grad with a cybersecurity focus would possibly have learned how to decompile and inspect sneaky code. Maybe trade them a decent color scheme for it?
 
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I got results from BinaryNinja on the first hex file.
I'm assuming what you need is the 2nd hex file, since it's much larger. But I didn't succeed on that one

Decompiler Explorer

Decompiler Explorer is an interactive online decompiler which shows equivalent C-like output of decompiled programs from many popular decompilers.
dogbolt.org dogbolt.org
 
As a retired programmer the answer is yes and no. Theoretically it is possible, BUT it's a massive undertaking. Object code exists because programs became too complex in the 1960's to use machine code. 2025 machine code is a million times more complex.

If you could get the object code, and setup a programming environment, then you could compile your own machine code.
 
AVR and PIC are both perfectly reasonable to program in assembly. Running the hex files through a disassembler and making the kinds of mods you're talking about isn't totally unreasonable. It's not a beginner project, but it is well within the realm of what's humanly possible.

Depending on how it was implemented, it might be possible to identify the tune data in the 1985 hex file and edit it directly with a hex editor. Using a disassembler is probably the easier route, though.

I'm not familiar with how the VFE bypass controller is set up, but if it's not doing too much, I wonder if just writing your own firmware from scratch would be a reasonable option.
 
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