@Douglas-Kryder The MT7688 does have four quite sophisticated hardware PWM units, however only two of them (pwm0, pwm1) have pins exposed on the Omega2. See here for some information , albeit in the context of generating WS281x LED signals.
@Igor-Silenock I have observed the same behavior with several Omegas2+. That is incomplete, halted boots when powered by 3.3V, then a successful boot when the power was increased to 3.4V. I did wonder if the digital meter on my bench power supply is accurate ... my VOM says it is, but in both cases this is measure of the least significant digit.
Okay now I can compile the firmware with the Codec for SGTL5000 I'm hanging again.
The kernel module is loaded but a cat /proc/asound/cards lists still --- so soundcards --- I'm not really sure but I think I just have a codec installed but no "card". Am I right if I think I need a card driver in build_dir/target-mipsel_24kc_musl/linux-ramips_mt7688/linux-4.4.52/sound/soc/mediatek which 'uses' the codec?
Does anyone know how to get this thing up and running? It's so exhausting...