Archer C7 v2 - Installing OpenWrt 18.06 directly from DD-WRT

I just bought a TP-Link Archer c7 v2, EU version with dd-wrt v3.0 already installed. But I would like to install OpenWrt to enjoy also the package collection.
A quick google research gives me this:
Since this aricle is a bit outdated (from 2013), I decided to read more about the steps and found the following links:

  1. httpss://

  2. httpss://

  3. httpp://

The first link is about the webrevert file in order to install back the original firmware. No problem here. But then, the second link learned me that TP-Link included some filechecker so as to stop the possibility to install third-party firmware on their products. But also that the serial number first four must be greater than 215C (Mine starts with 215B). So I found this third link which provides a original TP-Link firmware but without this filechecker.

As you might expect I'm kinda lost now what procedure should I follow in order to get OpenWrt installed on my router. I would greatly appreciate someone telling me the steps to follow in my case.

Best regards,

I'm not sure why you're lost...did you flash the OpenWrt image on the web GUI, yet?

Did it work?

From my readings, I have concluded that it is not possible to flash directly from dd wrt to openwrt. Thus, I need to go back first with the original firmware. My question is:

Do I need to take the original firmware from Tp-Link or the stripped firmware linked to the first post?