For this tutorial is raccomanded professional leadfree soldering iron
i solved my gps problem, it is hardware problem, so no settings, gpsaids and no other solution helped me.
Problem is caused by bad gnd conductivity between mainboard and antenna. It is conduced by:
1) CONDUCTIVE GUMMY (suggest me better name if you have ) This kind of rubber was used for old nokia 8210 for connect display to mainboard. It was the mayor fault for nokia 8210.
2) back cover gps antenna: When phone become hot, antenna go back and not good touch with motherboard. Then, when phone isn't hot, gps antenna remains with a kind of "hole"
First try software fix (it not helped me) then try my solution
Attention: it will avoid warranty, do it at your own risk, i'm not responsable for any fault.
here is antenna contact not used for my european i9000
Please check by yourself if it touch with your variant antenna,
if it is not used, you can remove and solder where was rubber
Now gps signal is immediate for me