Re: [stella] An Alternative Distro Method For ROM Hacks (Patches)

Subject: Re: [stella] An Alternative Distro Method For ROM Hacks (Patches)
From: "Fabrizio Zavagli" <rasty@xxxxxxxxx>
Date: Wed, 11 Dec 2002 23:12:18 +0100
Hello Chris!

> The downside is that creating a patch is going to be more work than
modifying a disassembled ROM directly (The procedure would likely be to keep
notes of all modifications and then reproduce them in patch form) unless I
can get clever and come up with a tool that will create the patch
automatically based on the original and modified ROMs (Hmm, might be
something to that...) Obviously I'm still in the preliminary stages of this.

Well, there's a format/tool generally used to patch ROMs called IPS Patcher
(some info at ). Guess there
should be an IPS generator somewhere also, that compares the 2 roms and
creates the patch..
If there isn't anyway, guess a file compare tool that records changes in IPS
format should be 100% feasible...

Docs on the IPS format can be found here:
Excerpt from the page:

- IPS files can patch every file not larger than 2^24-1 bits (2047 Mb)
- Every patch should not be larger than 2^16-1 bits (7.99 Mb)
- An IPS file can hold as many patches he can, assumed that the specified
offset and the size of every single patch doesn't overflow the specified

So target rom size is limited to 2mbits, guess that should be enough for
ol'VCS :)

Would be good starting using this method with the 2600!

Thanks and greets,

Archives (includes files) at
Unsub & more at

Current Thread