first step you need to do : 
prepare phone - 
remove battery, then connect TP to GND ( any GND on board will do job ), 
insert battery, press power on button, disconnect testpoint.

phone will be in emergency mode, if you did thigs properly.

then run s1tool.exe, select msm8974 emergency mode, 

press flash, select APP firmware part ( or select both APP + FSP + CDF +eLabel ) 
you can get APP + FSP from SEUS, is is "small" (~20mb)  and "big" (~750mb) files.
you CAN NOT use flashtool .FTF packages.

program will ask you to connect testpoint, but as you already prepared phone, just press "tespoint ready"
( or you can do testpoint from start, following program instuctions )

now insert usb cable to phone, drivers will be installed and phone will start booting.
when program will ask you to disconnect testpoint, just press "testpoint ready"
( or if you did testpoint procedure from start, disconnect testpoint and then press "testpoint ready" )

phone will load emergency s1 loader, then re-enumerate usb, load s1 loader and flash selected firmware.
after this, phone will be alive and kicking, if you not damage anything during disassemble.

