Hacking ROM Trimming - recommended??

[evilhomura89]

Hi guys,

Just wanna know whether ROM trimming is recommended or not...will it affect the stability and gameplay on flashcard using trimmed ROM?

 

[Vague Rant]

As long as you're using a good trimmer, it shouldn't have any effect on your playback of games. I've used NDSTokyoTrim and RToolDS (the latter is more of a ROM manager than just a trimmer), and both have proven to trim safely. I recommend it; it'll save you a whole lot of space, and if you find a game isn't working, you can always try it untrimmed and see if it works any better.

 

[evilhomura89]

untrim it??
never heard of untrim...i always thought it was a one-way process

i'm using dsbuff to trim some of my ROM though

 

[kobykaan]

untrim it??
never heard of untrim...i always thought it was a one-way process

i'm using dsbuff to trim some of my ROM though

who mentioned anything about UNTRIMMING a rom ??


the suggestion was to try it UNTRIMMED .. ie not trimmed at all or a clean untouched rom

 

[Bri]

I'm pretty sure I saw an "untrim" option on one of the ROM managers (can't remember which one). Presumably it keeps a copy of the trimmed part (or the entire untrimmed ROM) somewhere so that you can "undo" the trim.

Even if a ROM is overtrimmed, it will most likely only affect download play. If you don't use download play, you'll probably never notice a problem.

Anyway, you can always just grab a clean version of the ROM and replace your trimmed version if there's a problem. I use Rominator to trim all of mine, and have so far never had a problem.

-Bri

 

[Ferrariman]

Don't use DS buff, use something like NDSTokyoTrim.

 

[xalphax]

Don't use DS buff, use something like NDSTokyoTrim.

+1 for NDSTokyoTrim

 

[Searinox]

+10 for EZ-trim+. Extremly straightforward, very fast, supports archives, I trimmed through 40 games so far all 40 work fine with download play and wifi.

 

[DeMoN]

It really depends on chance and the game you're playing. Some games can not run on any flash cards if they are trimmed.

 

[DanTheManMS]

I'm pretty sure I saw an "untrim" option on one of the ROM managers (can't remember which one). Presumably it keeps a copy of the trimmed part (or the entire untrimmed ROM) somewhere so that you can "undo" the trim.

Trimming by definition doesn't modify the file in a way that can't be reversed. All trimming does is remove the empty data (tons of bytes consisting of either 00 or FF) from the end of the rom file. To untrim it, all you do is insert enough 00 or FF bytes to bring it back up to its original game size, which will be a power of 2. No need to waste space by keeping a copy of the untrimmed rom.

 

[Searinox]

Untrimming is REALLY unnecessary but if ya really want to do it what was said above works. I've done it before with save files that were smaller for an emulator but had fixed size on the flashcart. I added bytes to its end until it was original size. Really it doesn't matter if you add 00s or the letter A(65) or blank spaces(32), I added As. The file has all the data it needs to access within the untrimmed space and whatever is beyond that space doesn't even get read.

If the trimmed ROM was altered in a way that some data was lost or modified no untrim can guess what was there and restore it.

 

[Bri]

Trimming by definition doesn't modify the file in a way that can't be reversed. All trimming does is remove the empty data (tons of bytes consisting of either 00 or FF) from the end of the rom file. To untrim it, all you do is insert enough 00 or FF bytes to bring it back up to its original game size, which will be a power of 2. No need to waste space by keeping a copy of the untrimmed rom.

I assumed that if a ROM is overtrimmed, it's because it removed some actual data that was needed at the end (presumably data that isn't a 00 or FF), and therefore to restore it would have to store the data that was trimmed in order to return the ROM to its pre-trim state.

But it's possible that I misunderstand the problem with overtrimming. Is the issue that some games that require 00's or FF's at the end of the ROM for some reason? Does download play for some games require 00's or FF's at the end to work?

-Bri

 

[Rod]

It's not only recommended, it should be common knowledge between flashcart users!
I HIGHLY recommend NDSTokyoTrim (never gave me a single problem), and i DON'T recommend R4DS Rom Trimmer 2.0 (sure, it does its work, but it's slooow and ROMs get buggy here and there).

Trimming by definition doesn't modify the file in a way that can't be reversed. All trimming does is remove the empty data (tons of bytes consisting of either 00 or FF) from the end of the rom file. To untrim it, all you do is insert enough 00 or FF bytes to bring it back up to its original game size, which will be a power of 2. No need to waste space by keeping a copy of the untrimmed rom.

You know, I always keep a backup of ROMS in my PC, but when they're zipped with WinRAR there's virtually no size difference between a trimmed and untrimmed ROM. So isn't it just easier to keep a backup of the untrimmed one, and trim them all at once before putting them on a flashcard? Plus, japanese translated ROMs need to be clean to be patched, so it's two birds with one stone.

 

[blackwolf1006]

I trimed all the roms on my 8gb micro sd with the exception of Elite beat masters. it always crash my rom trimmer. After trimming the roms I end up getting a little over 1gb of free space. Some games drop 50mb other a few KB. but every little counts.

 

[DanTheManMS]

But it's possible that I misunderstand the problem with overtrimming. Is the issue that some games that require 00's or FF's at the end of the ROM for some reason? Does download play for some games require 00's or FF's at the end to work?
Correct. I'm not entirely certain why this is the case, but when referring to DS games "overtrimming" merely means taking away too many empty bytes. You only need to add a couple hundred extra bytes to fix the issue, so it's not really a big deal.

"Smart" trimmers read the filesize that the DS rom itself states it is, then trim to that point. This ensures that nothing necessary to playing the game is removed.

QUOTE(Rod @ Oct 23 2008, 06:13 PM) You know, I always keep a backup of ROMS in my PC, but when they're zipped with WinRAR there's virtually no size difference between a trimmed and untrimmed ROM. So isn't it just easier to keep a backup of the untrimmed one, and trim them all at once before putting them on a flashcard? Plus, japanese translated ROMs need to be clean to be patched, so it's two birds with one stone.

When in some compressed format, the empty data on the end will pretty much be compressed to almost nothing, just due to the way compression works. If you keep all your games in RAR format, then yes it would probably be just as easy to do that. Or you can store them uncompresed and untrimmed if you'd like. It's all up to personal preference.

 

[UltraMagnus]

exactly how much space can you save by trimming?

the only roms i have trimmed myself have been large gba roms

 

[currynoodles]

Absolutely! Some roms when trimmed can save you 50 MB. That's a lot of wasted space!!

 

[jaywilson]

off the top of my head mortal kombats rom size halves after trimming