Got it finally fixed, the following blog post didn't have the same phone as I do, but it gave me an idea what to search.
If you're about to reflash the same Android phone as I do, then get yourself ready for some headache, because LG has taken down the original source for this phone's firmware/ROM, so you have to look for the same (or almost same) firmware/ROM from third party sources, I did not manage to get ROM for Baltics, but I got one for UK, works fine and as a surprise I got Android 4.1 instead of 4.0.
About LG Flash Tool 2014, during the process of using this software you should install LG drivers by yourself first and might run into various problems, my two most common ones were that I didn't have download mode turned on at right moment and the error about that software didn't get connection to the server.
To turn on download mode, turn off your smartphone completely, take battery out for a moment (if you can) and then hold down both volume buttons, during that time plug in your USB cable (of course connect it to computer first) and release volume keys when the LG logo and "download mode" sign appears. If it starts to recharge, release volume buttons and turn off the phone or take battery out for a moment and try again.
If you're about to reflash your LG device and have further questions, feel free to ask me, because I went through all this ****.
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