Hacking DS to GBA mod : how to switch screens? Trying to emulate with R4 card..

[Panda is my username]

Hi!
My sister gave me her old DS lite. I would like to mod it into a Gameboy Macro

I would like to use my R4 card to emulate GBA roms (EZ flash IV is way too expensive, for me at least).
The thing is, my R4 (click here) boots GBA games on the top screen instead of on the bottom screen!

I am looking for some sort of screen switcher.
I found this.. http://www.cryptosystem.org/archives/2007/01/simple-gba-mode-switcher/
But how do I use it? o_o I can't code.

Thank you so much for your help!

Here is a picture of a Gameboy Macro :

 

[FAST6191]

You can't emulate GBA games in DS mode very well. http://ichfly.github.io/gbaemu4DS/ is the main thing people use if they do not have an enhanced flash cart like the DSTwo, ISMM or iplayer.

The thing you linked is more for those with a DS slot cart and a GBA slot cart

If the EZ4 is too expensive for your taste then you might instead look at a 3 in 1. http://www.modchip.ca/store/catalog/EZFlash-3-in-1-Memory-Expansion-Pack-for-NDS-Lite-p-16538.html (35 Canadian)

The screen a GBA cart uses can be set in the DS options.

 

[Panda is my username]

Thank you very much for your quick reply!

Thanks, I will use that emulator.

I'm not really interested in buying a GBA linker. I really can't boot slot 1 as slot 2/ switch screens?

Thank you so much for your help. I really appreciate it.