Author Topic: How to trim Byuu's Bahamut Lagoon rom 8MB->7MB to fit on Everdrive?  (Read 804 times)

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Offline bazookaben

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So Near (formerly byuu) recently put out a translation for Bahamut Lagoon that revamps the UI to look really good in English, but unfortunately it's 8MB and doesn't fit on an Everdrive by default.

However, on the release page he says
Quote
"The Everdrive will need a ROM trim to 7MB (safe to do!) first."

https://gbatemp.net/threads/new-english-translation-for-snes-strategy-rpg-bahamut-lagoon.579505/

But I'm I'm having trouble finding a program to do this. I tried using "Decrease ROM size" in WindHex" but the ROM it outputs has lots of corrupted text and eventually a crash.

Anybody know another program I should try?
« Last Edit: April 03, 2021, 04:32 AM by bazookaben »

Offline lee4

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trim by delete zeros end of 8mb rom
0x00700000 to 0x007FFFFF

then recalculate checksum of 7mb rom
ED64 v2.0, 3.0 & X7 | EDMD v3 | MEGAED X7 M15 v2.01 & PRO rev B | TED v2.4 | EDN8 v1.2N & Pro M19 N1 | SED v2.1 | SD2SNES rev E1 & PRO rev.B | EDGB v1.1 & X7 M17 rev B | EDGBA X5 M16 rev A & Mini M19 Rev B
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Offline nuu

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Ucon64 can fix the checksum for you after you trimmed it manually with a hexeditor like WindHex. Ucon64 is a command-line tool.

Offline bazookaben

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So if use Windhex's automatic rom size reduction,  it seems to be removing the last 1MB, which seems to be all zeroes.

Then I used ucon64 to fix checksum with - - chk, but the rom it outputs has the exact same problem.

So I'm not sure if I'm not recalculating the checksum corectly, and I'm not sure if I'm trimming correctly

Offline lee4

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STOP right there

Do NOT use Automatic Decrease ROM size Feature

Trim MUST BE done MANUALLY.

No shortcuts here
« Last Edit: April 05, 2021, 10:15 PM by lee4 »
ED64 v2.0, 3.0 & X7 | EDMD v3 | MEGAED X7 M15 v2.01 & PRO rev B | TED v2.4 | EDN8 v1.2N & Pro M19 N1 | SED v2.1 | SD2SNES rev E1 & PRO rev.B | EDGB v1.1 & X7 M17 rev B | EDGBA X5 M16 rev A & Mini M19 Rev B
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Offline bazookaben

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Ok, I manually removed the last megabyte, so now the last byte is "FA" at 006FFFFF.

Then ran "--chk" in ucon64.

I'm still getting the same text corruption. What am I doing wrong?

And to be clear about where the corruption happens, the bad text is only visible in certain menus and text boxes during a fight. In the intro story sequence, everything is fine.

Then after the first fight, during the next story sequence, the crash happens.
« Last Edit: April 07, 2021, 05:00 AM by bazookaben »

Offline nuu

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Actually the checksum fix isn't needed. The SNES has no means to check it if it's correct, unlike the Gameboy.

The ROM doesn't have a copier device header? There are tools that can tell you if it has a header or not. If you use the no-intro ROM there shouldn't be a header.

Offline lee4

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which Super Everdrive model you have ?
example
v1, China ver. , v2 or X5 ?
ED64 v2.0, 3.0 & X7 | EDMD v3 | MEGAED X7 M15 v2.01 & PRO rev B | TED v2.4 | EDN8 v1.2N & Pro M19 N1 | SED v2.1 | SD2SNES rev E1 & PRO rev.B | EDGB v1.1 & X7 M17 rev B | EDGBA X5 M16 rev A & Mini M19 Rev B
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Offline bazookaben

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v2.1, no DSP chip, manufactured in 2013. Purchased from Stone Age Gamer a few years ago.

I had to remove the original header on the JP rom to install the translation patch 1.1, found here:  https://near.sh/bahamut-lagoon
« Last Edit: April 07, 2021, 07:18 PM by bazookaben »

Offline lee4

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sound like "another" everdrive device also does not support max rom size :(
ED64 v2.0, 3.0 & X7 | EDMD v3 | MEGAED X7 M15 v2.01 & PRO rev B | TED v2.4 | EDN8 v1.2N & Pro M19 N1 | SED v2.1 | SD2SNES rev E1 & PRO rev.B | EDGB v1.1 & X7 M17 rev B | EDGBA X5 M16 rev A & Mini M19 Rev B
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Offline zaphro72

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sound like "another" everdrive device also does not support max rom size :(

Stone Age Gamer is an official Krikzz dealer so it should be a legitimate Everdrive

Offline bazookaben

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Could you guys do me a favor try this translation on your everdrives? On the v2.1 if you have one?

I'm trying to figure out if this is a bug or just my particular everdrive

Offline lee4

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sound like "another" everdrive device also does not support max rom size :(

Stone Age Gamer is an official Krikzz dealer so it should be a legitimate Everdrive
i meant by "another" also
super everdrive v2 says max rom  size is 7mb
everdrive gb says max rom  size is 8mb
everdrive 64 v2 says max rom  size is 64mb
mega everdrive x5 says max rom  size is 7mb

but in reality does not support max rom size
last bytes get corrupted
« Last Edit: April 08, 2021, 07:08 PM by lee4 »
ED64 v2.0, 3.0 & X7 | EDMD v3 | MEGAED X7 M15 v2.01 & PRO rev B | TED v2.4 | EDN8 v1.2N & Pro M19 N1 | SED v2.1 | SD2SNES rev E1 & PRO rev.B | EDGB v1.1 & X7 M17 rev B | EDGBA X5 M16 rev A & Mini M19 Rev B
RetroUSB AVS | Super NT | Mega SG | Super Retro Advance |  16bitPocket GBC | PCE+SSD3

Offline lee4

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Could you guys do me a favor try this translation on your everdrives? On the v2.1 if you have one?

I'm trying to figure out if this is a bug or just my particular everdrive
problem is last bytes get corrupted by os
as i try on my sed2 i got same corruption

i also try same "7"mb rom on sd2snes run fine no corruption
ED64 v2.0, 3.0 & X7 | EDMD v3 | MEGAED X7 M15 v2.01 & PRO rev B | TED v2.4 | EDN8 v1.2N & Pro M19 N1 | SED v2.1 | SD2SNES rev E1 & PRO rev.B | EDGB v1.1 & X7 M17 rev B | EDGBA X5 M16 rev A & Mini M19 Rev B
RetroUSB AVS | Super NT | Mega SG | Super Retro Advance |  16bitPocket GBC | PCE+SSD3

Offline bazookaben

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Do you have a guess to what the super everdrive's actual max rom size might be?

I wonder the rom could be carefully trimmed further