EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Total 1700; Flight Crew Type 750
Situational Awareness
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; Flight Crew Diverted
Aircraft
Previous crew that brought in aircraft we flew out wrote up some/fumes coming from the cockpit. Maintenance came and deferred pack 1 as they believe that was where the odor was coming from. Upon reaching cruise altitude of FL230; I smelled a strong burning odor; followed by the Flight Attendant and Captain smelling it. The Flight Attendant notified us there was smoke in the cabin. I began a priority handling descent after we put on 02 masks/goggles; and we agreed to divert to ZZZ. We [advised ATC] and landed in ZZZ. After landing and fully stopped on the runway; EICAS message 'PACK 2 OVERHEAT' was displayed. CFR looked over our aircraft; did not detect any hot zones; and followed us into the gate.  Smelled an order by myself; Flight Attendant; and then the Captain; followed by the Flight Attendant stating there was smoke in the cabin coming from rows 11-12. Have maintenance either look over issues more seriously or another aircraft used. We were assured by Maintenance the issue was from pack 1. The Head Maintenance Supervisor mentioned how he had been working since [a long shift] when he signed off on our aircraft. Fatigue may have been an issue.
EMB-145 First Officer reported the entire crew smelled a strong burning odor during cruise resulting in a diversion and uneventful landing.