AML-S905X-CC i2c pull-up resistors missing

Hardware
1

I can get i2c-ao and i2c-b enabled but both have terrible waveforms and fail to communicate to devices without external pullups. This is running the latest Ubuntu image.

Raspberry Pi 3B+ has 1.8k external pullups on GPIO2 and GPIO3 which makes I2C work correctly but Le Potato does not according to the schematic and measuring. Am I seeing this correctly? I verified the 60k ohm pullup from the Amlogic S905X is enabled but that’s too weak to run I2C at the 100KHz default frequency.

2

The schematics are available. These are general purpose IO with multiple functionality. Adding hardware pull ups would limit the other IO functions. If you have a peripheral that needs pull ups, it is recommended to add those to the peripheral.