Well I just need another mod­ule for my gp2x, so my gps recever will work… I’ll post here my steps I did to suc­cess­fully build the modules:

Get the ker­nel source:
#svn export http://svn.gp2x.com/gp2x/tag/kernel/2.0.0/

You need this tool­chain to build the mod­ules. Install it under /usr/local/arm-dev and add it to your PATH vari­able:
#export PATH=”$PATH:/usr/local/arm-dev/bin”

Edit the Make­file (Ker­nel­source) in the root dir and edit this line (line 24):
export CROSS_COMPILE = arm-linux–

Edit the ker­nel con­fig (#make menu­con­fig) and build the stuff:
# make dep
# make modules

Thats it, copy the mod­ules on your GP2X..

The most impor­tant thing (my opin­ion) is to choose the right tool­chain. The offi­cial GPH tool­chain any newer tool­chain will build your mod­ules but you cant load them:

[root@gp2x root]$insmod usb­se­r­ial
Using /lib/modules/2.4.25/kernel/drivers/usb/serial/usbserial.o
ins­mod: couldn’t find the ker­nel ver­sion the mod­ule was com­piled for