Ethiopian authorities reiterated that the deadly Boeing Co. 737 Max jet crash near Addis Ababa almost four years ago was mainly due to a faulty safety feature, revealing little fresh insight into the accident.

A final report into the Ethiopian Airlines Group incident concluded that all professionals and planes related to the crash were correctly certified, Dagmawit Moges, minister of transport & logistics, told reporters on Friday. The plane en route to Nairobi nosedived on March 10, 2019, killing all 157 people on board.

The incident followed another fatal Max crash in Indonesia the previous year and led to regulators grounding the model worldwide, plunging Boeing into crisis. The U.S. planemaker has since made revisions to the model and addressed safety concerns, and was cleared to return to the skies in its home market in late 2020.

Regulators in the European Union, UK, UAE and others followed suit, and Ethiopian Airlines itself returned the workhorse jet as a mainstay of the carrier's fleet in February. The company, Africa's largest airline, has taken delivery of five of the jets this year from Boeing, according to the planemaker's website, while Boeing has reached a legal settlement with families of those killed.

Ethiopia's latest report built on interim findings released in March 2020, and is long overdue. That's due to the complexity of compiling the report and challenges caused by the covid-19 pandemic, Dagmawit said. In further mitigation, the country has been embroiled in a lengthy regional war, with efforts to restore peace after two years of fighting between government and rebel forces being undermined by neighboring Eritrea.

Ethiopian's interim conclusions highlighted the role of a malfunctioning safety feature known as the Maneuvering Characteristics Augmentation System, to which Boeing has since made several changes. Further details are still to emerge with the report not yet publicly available.

Bloomberg"s Samuel Gebre and Julie Johnsson contributed to this report.