I'd been having the same issue with mine. I have a Relay module and an ethernet module connected.
I believe when it was occurring I had the 7 or 8 shorted with ground.
Not sure if thats the same case you have. I find it has no issue booting with the pin across to 3.3V.
I just saw this, here https://docs.onion.io/omega2-docs/expansion-dock.html :
- By default, the Serial, SPI, and I2C pins implement these communication protocols and cannot be used as GPIOs. Similarly, the I2S and PWM pins are set to GPIO mode by default.
I think it's that the default states of the pins 7/8/9 are not what we're trying to use them for.