Default [Q] Cannot boot G Pad 8.3

I have rooted my device following http://forum.xda-developers.com/show....php?t=2698267

Today the device asked me to update something (from LG), and I pressed it brainlessly.....and it crashed the OS

It then booted into the TWRP. Again, I wiped the system......

Now, the pad has no OS, and cannot be booted into TWRP or anything.

It keeps on show me the LG Logo and
Quote:
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Secure booting Error!
Cause: Device Unlock! So boot success!!
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Can anyone help? Any little suggestion will be appreciated