Air carrier Captain reported an altitude deviation and low altitude alert from ATC on final approach was the result of task saturation after an EICAS failure.

Narrative

While conducting a visual approach into Runway XX backed up by the ILS approach; the aircraft descended below preset altitude due to task saturation from an EICAS failure. The FO (First Officer) was instructed to set 2500 to prepare for inbound turn. The FO asked for gear down and at the same time the EICAS display red Xed and then went totally black. I went heads down to fix the EICAS issue by going to reversionary EICAS on the Captains side. While I was fixing the EICAS issue and task saturated the FO continued the descent to 2500 outside the ZZZZZ fix. It was briefed to be preset to 2500. While I was heads down fixing the EICAS issue we received a terrain alert from the aircraft and ATC. I Immediately took control of the aircraft and executed a climb to 3600 to recapture the glide slope. We followed the ILS system in and landed safely without incident.Task saturated due to maintenance issue; miscommunication; situational awareness in high task phase of flight.More situational awareness on both crew members part. More training on visual approach inside and outside of FAF.