The issue is that his tv is not showing the resolution which is used on first boot. I guess he owns a Hisense model?
Try another HDMI-Port onTV. Check the tv manual and tv settings.
The TV has four HDMI input.
I have two recivers with OpenPli v6.2 latest running in port 1-2.
In port 3 i have a DVD player.
These devices are running without failor.
In port 4 Gigablue.
If i used image factory 20170731 v1708 Team GigaBlue there is no problems.
If i used image Open Vix v5.1 latest there is no problems.
When using Team GigaBlue v6.1 lates,and OpenPli v6.2 latest i got troble.
With Open Pli v6.2 latest.
Reciver Display,when booting the first 5 sec.Team Blue logo
after 3 sec.the same logo on the tv.
then display gray
on tv no signal
then on display 1 sec. logo Open Pli v6.2
tv no signal
then on display 7 sec.logo Open Pli v6.2
the same on tv
then on display grafbar booting
on tv no signal
after booting complete,the display show the startup wizard.
The tv screen change to gray.
Best regards
Aage