Code:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<app version="1">
<name>mGBA</name>
<coder>Jeffrey Pfau (endrift)</coder>
<version>0.4-2809-9a538f8</version>
<short_description>mGBA Game Boy Advance emulator</short_description>
<arguments>
<arg>-rom</arg>
<arg>sd:/roms/My rom.gba</arg>
<arg>-r</arg>
<arg>2</arg>
<arg>-reduceScale</arg>
<arg>75</arg>
</arguments>
</app>
Also, if you want to change pad layout you can add this lines to <arguments> </arguments> section:
Code:
<arg>-button_A</a>
<arg>B</arg>
<arg>-button_B</arg>
<arg>Y</arg>
Hope this helps