If you're interested in a little tinkering, you could try flashing Siyah v6 beta 5 kernel via odin, and see if your phone boots up. Siyah v6 supports JB 4.1.2, and it will replace your current kernel. So, theoretically, your phone should boot back up.
Yeah that's what I did Donnie and it worked a charm, thanks to both you and immortalneo.
Just to confirm I can go ahead and install any rom now without fear of the "superbrick" bug? or would I still need to source an insecure kernel first?
Thanks again, it's a load off my mind
No problem, good for you.
This brickbug can only appear in stock 4.0.4 recovery, so you are safe.
You can try to flash other kernels (.zip files) as well through CWM. But pay attention that you search for the right ones, that are made for your device and your Android version.
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