I had the time yesterday to start building my next Zynthian (I wanted to test Aeolus )
I used the AudioInjector board, an unknown HDMI 7" display with touch, and a USB MIDI Interface, starting with the official image.
I had to retry 4 times
The first fail was caused by the webconf and the software updates that removed my custom HDMI parameters in config.txt. THRICE!
The last was caused by default alsa settings that are not suitable for audioinjector. Solved by restoring settings found here: https://github.com/Audio-Injector/stereo-and-zero
BTW: Yes, as someone alreaty stated, the AudioInjector 40pin connector quality is abysmal and soldering is… well… I have no word to describe it. My first solders when I was a child were way better than those on the board.
Anyway… now it works…