After I went through the create edid process, I used the following command to check the contents.
edid-decode ~/.config/firmware/edid/edid-HDMI-A-1.bin
Change to edid-HDMI-A-2.bin if checking second hdmi port
You can use the internal script "dump-active-edids" (it's used by "getedid" on RPi) to write the edids of all connected displays to /storage/.config/firmware/edid
It'll tell you which HDMI/DisplayPort/... connections it detected, for each one it created a edid-<NAME_OF_CONNECTOR>.bin file - which you can then simply decode with edid-decode.
eg here on RPi4 with one display connected to the first HDMI port (edid-decode cut down for brevity):
xbmc:~ # dump-active-edids
found active connector(s) HDMI-A-1
xbmc:~ # edid-decode /storage/.config/firmware/edid/edid-HDMI-A-1.bin
edid-decode (hex):
...
Block 0, Base EDID:
EDID Structure Version & Revision: 1.3
Vendor & Product Identification:
Manufacturer: GSM
Model: 1
Serial Number: 16843009
Made in: week 1 of 2018
...You could also check through all the connectors in /sys/class/drm/, verify if the status reports "connected" and then use the edid file from there (eg /sys/class/drm/card0-HDMI-A-1/edid) - this is basically what that script does - but as card, and connector names may change it's probably easier to let the script deal with that 
BTW: so far we only tested the script on RPi, it should work on all other devices though, so if you have issue or notice something odd please tell us about it so we can fix/improve it.
so long,
Hias
so long,
Hias
