Same problem here. With any 1.6 firmwares my gps don`t work, I put my phone under clear sky more than 1 hour and no gps found.
With 1.5 firmware I find in 5 second full gps signal. I fing gps in my house with 1.5 original firmware.
I don`t know why with 1.6 Donut my gps don`t work
Sorry for my english