not a BIG problem. I can say that because my phone had not been activated yet so I wasn't going to kill my service doing this.
YEAH!! - I just accomplished this feat
I can't give u the blow-by-blow detail but basically.
I used RSDLite5.6 and flashed VRZ_XT610_4.6.8_user_signed_1FF.sbf
I had a big issue with a function stopping unexpectedly. I got it to a half stable state by continually touching FORCE STOP.
I then tried flashing DROIDPRO_2.26.20_FULL.sbf. Not much better luck here - same error different program.
I then went back to flash VRZ_XT610_4.6.8_user_signed_1FF.sbf.
When I did this I had to keep hitting FORCE STOP on the error popup to allow the flash to proceed.
That is the part I can't explain so just be persistent.
This time it worked and everything was stable.
I the used Superoneclick to root. When I used this before on 4.7.3 it stopped at step 7 as others r reporting.
This time - no problem.
Installed OTA Rootkeeper, Superuser, Titanium backup and reflashed with 4.7.3.XT610.Verizon.en.US
YMMV - but it takes persistence.
U may be able to just flash the 4.6.8 a couple times instead of going back and forth. Then again it might work the first time for u.
Anyway - it can be done but if it is on a active phone u might want to have a spare to activate just in case.
I am fully functional and activated now.