4.1 jelly bean - Flashed my phone without rooting and now it doesn't work

I have an international Samsung Galaxy SIII i.e. GT-I9300.

Few days after the official upgrade to v4.1, it started freezing. So I removed the battery and inserted again and it did not boot and was stuck at the boot logo. It doesn't start with the recovery mode either but it does start in download mode.

So I flashed it with odin to leaked Galaxy SIII v4.1.2 build.

Now it shows 'custom binary count to one'. But when I boot it, it still doesn't start. (same issue; it gets stuck in the boot logo).

I'd also like to mention that the phone was not rooted prior to flashing.

I don't care about data now, I just need my phone back.