thats the correct cable, u need a working w810i gdfs to use a as a template theres 1 in the download section, u can use GDFSEdit - SE-NSE Forums to edit the CDA etc to match ur phone,
then u need SEMC 8.4 cracked also in download section it's a cracked there for free version, then u use this to write ur oringal old imei number which u can find on the side of the box the phone came in or old setool logs, now u use semc to flash and write in ur imei number to the new gdfs then do a full flash and ur phone should work