As I showed you, with your GNex, just flash the stock firmware, via Odi (This time, not with fastboot) ^^
Check out this website, and download the desired ROM, there... Sammobile.com/firmware/
---------- Post added at 01:47 PM ---------- Previous post was at 01:43 PM ----------
Fassies are just about unbrickable.. unless you have some sort of hardware issue. Its been the case for me more than once where I bricked my device and couldn't get into recovery but download mode worked just fine. Just hold volume down as you plug your device into your PC.
EDIT: For clear instructions to put your fassy into download mode
Sent from my SCH-I500 using Tapatalk 2
I've bricked my SGS II just by reboooting it, into Odin download mode ^^
You just need to flash the phone/wipe the phone, in the wrong moment (Example: When it's updating the factory binaries).
And, if a collegue of mine, can brick an old (2003 model) Nokia, then this can brick aswell ^^