I have two Raspberry Pi's both model B revision 2, both running the most recent version of Arch Linux from NOOBS. I have tried my best to replicate the install procedure to get i2c working on both systems, but it is hard considering there is no official wiki post. Anyways, I can run
i2cdetect -y 1
on both of my Pi's, but only one will show the i2c device connected. The address of the sensor is 0x68, it is the MCP3422. Strangely, on the Pi that won't recognize the device, it shows an address as UU, but it is not the address of my device, and also it will not connect to WiFi when the sensor is attached. Unfortunately the Pi that isn't working is actually part of field research, so my debugging abilities are limited.
I would like know the best way to debug this issue with limited access to resources.