I replied to all 3 amazon sellers to give 1 star reviews and photos.
Please rate your own seller on aliexpress with 1 star review too.
In the meantime I received the blank board unsoldered, soldered it myself the correct way and it works fine.
With
root@DietPi:~# ~/rpi-rgb-led-matrix/examples-api-use/demo --led-slowdown-gpio=4 --led-panel-type=FM6126 --led-rows=64 --led-cols=128 --led-row-addr-type=3 --led-chain=1 --led-parallel=2 --led-show-refresh --led-scan-mode=1 --led-pwm-bits=4 --led-pwm-lsb-nanoseconds=50 -D0 --led-pwm-dither-bits=1
I get 350Hz on 2 ABC panels (128x128 total res)
This shows the correctly soldered board on left, then the incorrect one, the incorrect one I tried to unsolder (oh boy, what a mess), and a blank board with the connectors put in the correct way (not soldered yet)
