Connecting a Sony Ericsson P1i to a Windows 7 x64 Computer in Phone Mode

You need to get a driver package, google for “p1_usb_signed_drivers” (p1_usb_signed_drivers.rar).
Note for myself: I’ve sent an e-mail to myself with these drivers as an attachment in case I can’t find them later.

This assumes that: 1. you don’t have any drivers installed, 2. you don’t have PC Suite installed. Otherwise you may need to do the steps differently.

1. Install PC Suite for Sony Ericsson from their support site, the version for your device, and restart.
2. Connect your phone to the USB cable and let it install the wrong drivers that it does automatically automatically.
3. Uninstall old drivers (very important, in device manager uninstall and check the “delete drivers” checkbox on: “Ports Com&LPT->Sony Ericsson … something”, “Universal Serial Bus Controllers->Sony Ericsson … somethin” (there should be 2 listed))
4. Disconnect your phone from USB
5. Restart Windows
6. Unpack the p1_usb_signed_drivers package
7. Right click the setup.exe and choose “Vista” compatibility mode, apply.
8. Right click the setup.exe and choose run as administrator and install
   (If there are any errors with this driver package you will have to uninstall and reinstall it and reboot until it works, and maybe try other compatibility modes)
9. If the drivers were successfully installed, disconnect from the Internet, so that it doesn’t automatically download wrong drivers when you connect your phone.
10. Once disconnected from the Internet, connect your phone, and it should find the drivers and the mrouter driver.

You may need to do the steps differently if you don’t have the drivers already installed, or PC suite already installed.

Source: http://social.technet.microsoft.com/Forums/en/w7itproappcompat/thread/47fe4ea2-7d73-4615-9a7e-5f5dd4ff8546

UPDATE (Dec 7/ 09):  For me, this method was kind of on and off.  I used this method and it worked, but then after I reinstalled the firmware on my phone, PC Suite was no longer able to identify my phone anymore.  I uninstalled the drivers from device manager, and let Windows 7 install my drivers for again and it worked.  I guess I can’t really narrow down which method works, but this is worth a shot I guess for those who are looking for solutions