When flashing from a Linux PC, my method to flash is to remove the battery, run flasher command replace battery, and insert usb cable. From the wiki Reading other parts of the wiki, it appears that pressing U is important when flashing from a Windows setup to enable drivers to be installed. This is genuinely not the case from an Ubuntu Linux setup when I have flashed my device in the past. In fact I need to do a reflash over the next couple of days, so I'll try it to confirm.