Waffle - HDMI no signal

Hello,
I got the same problem. The board was displaying the bios using hdmi but when I flashed bios version 193 I could not get hdmi output anymore. The flashing process didn’t give any errors. I also tried newer bios versions with same negative results.
I can connect to the board using serial connection. It seems to recognize the display when I execute xrandr -q. If I reboot the board it displays the whole boot sequence. These are the last commands before stopping:

[ 12.378641] Bluetooth: RFCOMM ver 1.11
[ 12.820056] HDMI HDA Codec ehdaudio0D1: HDMI: failed to get afg sub nodes
[ 12.827761] HDMI HDA Codec ehdaudio0D1: Failed in parse and map nid with err: -22
[ 12.836166] HDMI HDA Codec: probe of ehdaudio0D1 failed with error -22

It seems to be some sort of hdmi error. Any idea how to correct the issue?
Thanks