I've seen some vpn providers with openwrt tutorials about ovpn but really not much. I dont know why, even if some say that dd wrt is dead, all vpn have their ddwrt/ovpn tutorial and about nothing on openwrt.....?
So , Express_VPN does not have tuto on owrt, and their ovpn config files are for dd wrt.... and I tried to use it with openwrt but does not work. Yes I'm a novice, I've read on it, but I saw a lot of tuto, as i said, with a real ovpn files for open wrt but many times it is with scripts... but vs dd wrt it seems always hard..
It should be relatively easy if expressvpn does provide *.ovpn configuration files. You can follow almost any other openvpn tutorial for openwrt to set it up. For a specific ExpressVPN setup guide maybe take a look here: Setup Expressvpn on WRT32x
Then you only need to download the needed packages and setup the firewall correctly. It's actualy quite simple to setup a OpenVPN client on OpenWrt. With the Luci-OpenVpn-App you will have the option to upload the *.ovpn configuration file and setup your VPN credentials. I would follow a recent OpenVPN guide for OpenWrt (firewall part) and then combine it with your expressVPN ovpn configuration file. It should work out just fine! Before you start with your OpenVPN setup I would suggest to make a config backup via Luci (just in case).
Btw, if you are looking for a Firmware build which is providing all the needed packages for a OpenVPN setup I would suggest to take a look into the builds of davidc502: Davidc502- wrt1200ac wrt1900acx wrt3200acm wrt32x builds
I'm running these builds* with my WRT3200ACM for over a year and never had any issues with my VPN connection and I'm using the VPN Policy Routing package by @stangri to only route specific devices, ports and/or remote adresses over the VPN connection.
(*the current build of davidc seem to have some trouble with port forwarding for some people, so I'm still using the r11829 build)
Davids Build are based on the latest snapshots and have alot of packages included out of the box (eg. Adblock, UPNP, OpenVPN dnscrypt-proxy V2), so no. However afaik the Wifi driver and firmware are the same as in the latest OpenWrt Release, so don't expect better Wifi performance when using a build of davidc502.
See: https://dc502wrt.org/faq/
You can easily setup OpenVPN with the latest Release of OpenWrt (19.07.1), I just suggested the builds of davidc502 because you mentioned that you feel like it's harder to setup OpenVPN with OpenWrt (vs DD-WRT). In my opinion it's not very difficult as you can follow almost any recent guide on how to setup OpenVPN in OpenWrt. The Firewall config part is also quite easy if you follow a guide and everything can be setup via Luci.
If you have trouble with your OpenVpn setup just ask here and I'm pretty sure that someone will help you out as there are plenty of helpful people in this forum but a little personal commitment is always welcome and needed.
Out of the box there is no Wireguard package in the builds of davidc installed but I heard it's quite easy to set up a Wireguard client in OpenWrt. My VPN provider doesn't support Wireguard at the moment so I have no clue how to set it up.
You can upgrade from official OpenWrt to a OpenWrt Snapshot Build without going back to the OEM firmware. Read the FAQ on davids site (Number 2, b+c). In your case I would flash the .img via SSH to make sure you start fresh with davids build.
What's the difference between images ending with .img and .bin?
a .img is used to originally flash OpenWrt from a browser if coming from stock Linksys firmware.
b .bin is used for upgrading if already running OpenWrt: either from a browser (LuCi) or from a SSH terminal.
Example command using SSH: "sysupgrade /tmp/imageName.bin" OR "sysupgrade http://webLocationOfImage.bin"
c. If currently running OpenWrt, .img can also be used from SSH for a completely fresh start.
This is not normally needed, except possibly if you are changing distros (i.e. going from official OpenWrt to @david's build).
Give your router a couble of minutes and then log into the Web GUI with the default IP Adresss(192.168.1.1). You could then try to upload you old config or start confgure the device from the scratch (recommended). Keep in mind that Wifi is disabled by default in OpenWrt...
on putty, it says :: Image metadata not found
Use sysupgrade -F to override this check when downgrading or flashing to vendor firmware
Image check failed.
