News: 11 March 2016 - Forum Rules

Author Topic: Patching on carts using Retron  (Read 2533 times)

werewolfslayr925

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Patching on carts using Retron
« on: March 19, 2016, 05:44:10 pm »
Hello, all! Newcomer here.

I'm beginning to get into importing games from Japan and patching them using the Retron5's patching capabilities. Needless to say, the wonderful work on this site has been indispensable in playing translations of games never released outside of Japan. However, sometimes the patches won't work on certain cartridges and I assume that it may be a header issue. From lurking and research, I've found that you can determine whether or not a ROM has a header by the ROM's size, so is it possible to determine the size of a game before I purchase it - i.e. is there an easy way to determine the ROM size from some marking on a chip or something? Or am I just going to have to gamble with buying carts and hope that if it needs a header the ROM has a header and if it requires no header that the ROM doesn't have one?

Also, if this is the wrong place to ask this kind of question, please let me know so I can go sit in the corner.
As the harbor is welcome to the sailor, so is the last line to the scribe.

vortex

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Re: Patching on carts using Retron
« Reply #1 on: March 19, 2016, 06:46:48 pm »
Quote
I'm beginning to get into importing games from Japan and patching them using the Retron5's patching capabilities. Needless to say, the wonderful work on this site has been indispensable in playing translations of games never released outside of Japan. However, sometimes the patches won't work on certain cartridges and I assume that it may be a header issue. From lurking and research, I've found that you can determine whether or not a ROM has a header by the ROM's size, so is it possible to determine the size of a game before I purchase it - i.e. is there an easy way to determine the ROM size from some marking on a chip or something? Or am I just going to have to gamble with buying carts and hope that if it needs a header the ROM has a header and if it requires no header that the ROM doesn't have one?
This can be a problem since you can not manipulate with the cart like you can with the ROM file.

Not only can not see the size, you also can not see the code, unless you scan the cart back into a ROM file again. You thus can not calculate the CRC (checksum id) of your rom. Since the header might not be the only issue.

Usually carts don't have headers by default, since this is a leftover by the copier, but you never know.

It can be another problem, if the patch is made for the headered rom, and you have a cart without a header. You then need to use a PC in any case, to patch to a headered rom file.
You need to get the rom file of your game and patch it correctly (header, region). This is not a problem on a PC, where you have multiple options.

Once the correct rom is patched and the hack works and is tested (on emulators), make another IPS using Lunar IPS by comparing the hack with the original non headered rom. This IPS should then work with your cart.

In any case, if you buy a cart, it doesn't matter if it is headered or not, you can make a working IPS in any case.

You can even make multiple IPS files. For instance create IPS by comparing (using Lunar IPS) a working hack (rom file) with US, EU and J original rom files, all headered and non headered. You will thus get 6 IPS files. Once of them must work with your cart on Retron.

You are also required to do the same if the patch on the site is UPS or Xdelta patch (instead of IPS).

Spinner 8

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Re: Patching on carts using Retron
« Reply #2 on: March 20, 2016, 03:47:23 am »
This can be a problem since you can not manipulate with the cart like you can with the ROM file.

Not only can not see the size, you also can not see the code, unless you scan the cart back into a ROM file again. You thus can not calculate the CRC (checksum id) of your rom. Since the header might not be the only issue.

Usually carts don't have headers by default, since this is a leftover by the copier, but you never know.

It can be another problem, if the patch is made for the headered rom, and you have a cart without a header. You then need to use a PC in any case, to patch to a headered rom file.
You need to get the rom file of your game and patch it correctly (header, region). This is not a problem on a PC, where you have multiple options.

Once the correct rom is patched and the hack works and is tested (on emulators), make another IPS using Lunar IPS by comparing the hack with the original non headered rom. This IPS should then work with your cart.

In any case, if you buy a cart, it doesn't matter if it is headered or not, you can make a working IPS in any case.

You can even make multiple IPS files. For instance create IPS by comparing (using Lunar IPS) a working hack (rom file) with US, EU and J original rom files, all headered and non headered. You will thus get 6 IPS files. Once of them must work with your cart on Retron.

You are also required to do the same if the patch on the site is UPS or Xdelta patch (instead of IPS).

To clarify:

Headers aren't part of the game or cartridge itself - the header (just some information about the ROM's size and type) is added to the ROM file by the copier tool when the ROM is dumped. So the cartridges the Retron plays will never have a header.

The problem is, a lot of patches are intended to be used on a headered ROM. And, there's not an easy way around that. You can:

  • modify the patch itself and subtract 512 bytes from every address it references (a tool to do just such a thing would be pretty simple...),
  • or you can do like vortex said: patch a headered ROM, remove the header, then create a new patch using that ROM.
  • Or wait for someone else to do either of those. :)

Either way, you'd have a patch that works with cartridges on Retron.

vortex

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Re: Patching on carts using Retron
« Reply #3 on: March 20, 2016, 07:41:27 am »
Quote
Headers aren't part of the game or cartridge itself - the header (just some information about the ROM's size and type) is added to the ROM file by the copier tool when the ROM is dumped. So the cartridges the Retron plays will never have a header.
Thank you for confirming that. I thought it was so, but I wasn't sure.
I guess the original poster might have a lot of work to do, if he wants to play SMW hacks (since all patches are made for the headered rom).

Editing the existing IPS might be possible with something like this program (IPS peek).
http://www.romhacking.net/utilities/1038/


R9delta

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Re: Patching on carts using Retron
« Reply #4 on: March 22, 2016, 12:03:49 pm »
What Vortex and Spinner elaborated on is the best approach for this issue. I've been doing that for at least a year and a half now (since the R5 introduced using patches) and it's worked out fine. If you have a lot of imports and you don't have the time you can download all the patches i've fixed for the Retron 5 here:

https://www.mediafire.com/#b5kjabm681te5