I have the HDMI-to-VGA adapter with the bad EDID. The monitor says "unsupported mode" on the mode that should be supported. The 1600x900 mode don't work, only the 1280x720. The virtual console is broken.
Using the EDID override, I was able to set 1440x900 mode in both X and console. That however prevented ALSA from working. Even with the original EDID dump.
There's no visible difference in the system. Pulseaudio have the same playback device. Aplay works the same. The only difference is no sound.
By the way, the system is Allwinner H3.
Add: I used Deltacast E-EDID for patching. Just took default edid/1440x900.bin and added a CEA extension block.