well in the first place you havent fried your mainboard, the fault lies with the usb . 2ndly its a development fone.. just as nokia said step 4/5.. hence your usage of power kernel signifies your development intentions.. you are only liable if you fry your processor which aint the case here.. last but not the least nokia repair guys are ******s ..they only know how to flash..reflash or check the hardware issue..they cant differentiate between custom and stock symbian fw forget undsting a linux device.. just give em da darn device and everything will be fine..trust me..have indepth experience in dealing with em.. no matter wah country..they all da same