In order to ping 192.168.78.1 from inside Mik2 I need to add a route in Mik2 and route all traffic to 192.168.78.1 from the pptp interface. But even when I do that, the DHCP is not working.
1. Try SSTP, it has a larger MTU
2. Set keepalive on both eoip tunnels
3. Try to set DHCP server and gateway only on eoip and client on the other end and see if it works, exclude bridges.
I had a problem with bridges with two hEX: when the second hEX (all ethernet bridged) was connected to the first one that has another bridge, WhatsApp images were taking too much to download, same with apps.
I've made a reset on the second hEX and configured it again manually and the problem is solved.
I don't know why but 6.43 has something that make bridges created in older versions to work bad.
Now I have the same configuration I had before 6.43, nothing different, but I don't have problems anymore.