I have an usb wifi device (a Ralink) that i'd like to use with my EV3 brick. The device works correctly on linux, and I already know model, chipset and required linux modules. I've taken a look to the ev3 image, and i noticed the netmods subfolder witch appear to contain a module for realtek devices (not currently listed as supported?), that gets copied to the kernel modules folder by update_sdcard.sh. Am i right? If so, i guess i should cross-compile my modules agains the correct linux kernel and then copy them in netmods.
Is there any guide/howto/tutorial to build this modules? Thanks.
Yep that is pretty much what you need to do. If you run into trouble you may want to wait a couple of days as I plan to push a new update that contains the build stuff for the module I've added and this will probably be helpful for you in adding new modules.