I couldn’t spot this in the forums, but I’ve ran into this before. The initial installation on the TV went well and then the PI rebooted, and after a second it switched to ‘hdmi unsupported’ (with nothing but a blue screen).
I’ve got an older Konka TV and found it was necessary to add this to config.txt
hdmi_force_edid_audio=1
hdmi_ignore_cec_init=1
hdmi_group=1
hdmi_mode=16
The various hdmi modes are explained here:
I had previously had success with hdmi_mode=4 (720p), but was fairly sure my TV was 1080p, and sure enough ‘16’ worked for me.