This version of grit adds an option (-mp) which allows you to specifiy the palette number for map's. This is handy if your using 16 color tiles and need to share a palette and the palette isn't at entry 0.
Just copy the files over C:\devkitPro\devkitARM\bin
To use palette 15 for example add the following to your grit file
-mp15
Thanks for Jasper for the help getting grit to compile.