Cameroon captain Vincent Aboubakar scored his fifth goal of the Africa Cup of Nations and his already-qualified side were joined by Burkina Faso on Monday in the second round.
The Saudi Arabia-based forward, who turns 30 on Saturday, put Cameroon ahead and substitute Garry Rodrigues equalised for Cape Verde after half-time in a 1-1 draw in Yaounde.
Cyrille Bayala put Burkina Faso in front and Getaneh Kebede levelled for Ethiopia from a penalty in Bafoussam in another 1-1 draw that was enough to take the west Africans through.
Cameroon topped the final group table with seven points. Burkina Faso edged Cape Verde on head-to-head records for second place after both accumulated four points. Ethiopia were eliminated with just one point.
While Cameroon and Burkina Faso are assured of last-16 places, Cape Verde must wait to see if they go through as one of the best four third-placed teams from the six groups.
Cameroon will remain in Yaounde to play a third-placed team on January 24, a day after Burkina Faso meet the Group C runners-up in Limbe.
Should Cape Verde survive, they will play the winners of Group B or Group C in Bafoussam or Yaounde on January 25.
"We won the group, which was our goal, although we wanted to win all our matches. We will continue to play here in Olembe," said Cameroon coach Toni Conceicao.
"We had many chances. The Cameroonian team was not brilliant but still played a good game. We can do better, but if we take an overall reading, we were superior to our opponents in the group."
Aboubakar is the first Cameroonian to score in all three group matches at a Cup of Nations since Samuel Eto'o achieved the feat with five goals at the 2008 finals in Ghana.