Methods, systems, apparatuses and program products are disclosed for communications such as may be used for debugging computers and similar electronic products at a level suitable for low level firmware. This may find application, for example, in environments after cache initialization around the time of memory bring up or motherboard device enumeration but including durability into and beyond software loading.GPIO (General Purpose input/output) connections may be used for communication that may, for some purposes, be regarded as half-duplex but without necessarily being anisochronous.