Hacking EZ-Flash IV Homebrew

[Rolling]

Hi GBA/EZ-Flash experts!

I hope i'm in the right forum for this question...

I made a little homebrew program based on gsm player to play some audio files on my GBA. It works fine with emulators like vboyadvance oder no$gba but when i try to run it on my EZ-Flash IV i just get a blank screen.

Am i missing something? Every other ROM (non-homebrew) works fine.

Kind regards,
Rolling

 

[FAST6191]

The same issue I am about to cover applies to all flash carts, more accurate emulators, and could happen to any piece of homebrew.

While Tepple's GSM player is usually a bit better on this front than the competition (neimod's music player advance
http://www.gameboy-advance.net/emulated/musicplayer_advance_gba_mp3.htm ) the header is usually broken (despite various rulings before then for part of the GBA era a lot of homebrew devs did not include a header for they feared it was illegal). I can't remember what the current (or older) commands for soft reset are so probably better to look at fixing the header.
GBATA from
http://www.no-intro.org/tools.htm
flash advance toolkit
http://www.gameboy-advance.net/rom_tools/flash_advance_toolkit.htm

GBATA will fix minor issues with header, FAT will create one where it does not exist. Sometimes I had to combine the two (use FAT then fix any issues with GBATA).

The other issue is possibly the size of it -- depending upon your EZ4 model you might be limited to 16 megabytes if doing RAM, 32 for NOR.

 

[Rolling]

Hi Fast6191,

thanks for you quick resonse!

Didn't know about FAT yet, but i already tried GBATA...

I did some further research. Both tools show me that header is ok. I tried to fix it but i still can't get it to work (see images attached).

I also tried to pad the file (7014kb) to 8192kb but no success. Other ROMs with 8192 size work fine.

I'm lost

 

[Rolling]

Hi *,

today i received a Supercard SD Mini to try if it is an EZ-Flash related issue.

Same result - white screen.

 

[Deleted User]

GBATA is showing that the rom has a bad checksum. Try using uCON64 (https://ucon64.sourceforge.io/) to correct it. Make sure download the GUI (half way down the page, extract it into the same folder as uCON64) or you'll be stuck using the command prompt.

 

[Rolling]

Hi PsxFan,

i went with your advice and fixed the checksum with ucon. GBATA confirms that header (and checksum) are ok. I tried the updated rom with Supercard and Ez-Flash, but sadly to no avail.

I thought maybe something is wrong with my coding so i took original gsmplayer files (since i'm a new member i'm not allowed to post a github link, but you can easily find it on github by searching "gsmplayer-gba") and compiled a clean rom. To my surprise i also couldn't get "clean gsm" to run on gba hardware (white screen).

So i guess my question is how to get GSM player to run on real hardware?

 

[Deleted User]

Ok. I compiled it and tried it myself and it's working fine on my hardware (both my EZ Flash IV and EZ-Flash Omega). With the EZ Flash IV you need to launch the game with L + B or add it to the list of non-patched games in the EZ IV's config file (You will need to edit the 4 bytes at 0xAC (Game ID Characters) to something that can be uniquely identified).

 

[Rolling]

OMG, dude - you are a legend!

How could i've missed that?! Now i got it to run on EZ-Flash with both solutions.

PS: Fun fact - i've also managed to run it on Supercard. Basically it was the same mistake - i patched the rom (because all other roms need a patch), but the card wanted it unpatched.

Big thanks to you!