strait from
http://theidoctor.org/omnia.html
STEP 1: Make sure that the active sync connections on your computer is set so to *DO NOT ALLOW USB CONNECTIONS.
Step 2: In your phone settings, switch the USB connection from active sync to sync with Mass Storage. Then turn off your phone until later.
Step 3: Open the Samsung Omnia UMDL
Step 4: Select Unified Image File (*img) and search for the samsung i910 firmware (i910WM6.1.REV10.CC20.VZW.img)
Step 5: Click the detect button
Step 6: Plug in your phone while it is still turned off.
Step 7: When you plug it in, turn on the phone.
Step8: Your phone should have been detected and the firmware should be written to the disc. Wait for the blue highlight on the UMDL.
Step 9: It should be rebooting and you will need to setup windows again.
Step 10: To turn the GPS on, go to settings -> Phone -> GPS -> Change settings from 911 to location on.
Step 11: Soft reset the phone