Hi Nate,<br />Thanks! I've looked at the basics of I2C, but I've seen from the iGFX PRM that GMBUS implements some registers and error handling the NAKs differently, but I guess that I'll be dealing with that later.<br /><br />Yeah, I was thinking that if we wanted debug up as soon as possible, then the iGFX BAR and P2SB GPIOs would have to be programmed, so that sounds about right. Synchronising with the FSP's config is probably important too, but I suppose you implemented that/we'll see?<br /><br />For now, I have a proposal at <a href="https://docs.google.com/document/d/1CyyerMfPwvZxkBjfE_-H1OlkZPxH98uqpmb9tBAV_ps" target="_blank" rel="noopener">https://docs.google.com/document/d/1CyyerMfPwvZxkBjfE_-H1OlkZPxH98uqpmb9tBAV_ps</a>.<br /><br />Best regards,<br />Benjamin