2 out of 4 boards present a problem with internet (ethernet)

[g_t_j]

Play around with the rx and tx delay values in https://github.com/longsleep/build-pine6...2562-L2563 and check if you can find values where the non working board start working.

Thanks for your answer.

Is there by any chance a tutorial for this procedure? This is completely new to me. Do I have to obtain these values through Ubuntu?

Since I made the post, I did another test. I tested the 2 ''working'' boards with xbuntu and run speedtest net. 
Both boards reached the maximum potential of my internet speed - 74 mbps download / 5 mbps upload. Also tested the 2 ''non-working'' ones again and they performed 2.4mbps download / 5mbps upload  and 5mbps download / 5mbps upload respectively.