Boeing  (BA - Get Report) shares rose Thursday after officials in Ethiopia said the 737 MAX 8 plane that crashed shortly after takeoff last month was airworthy and that pilots followed all proper procedures prior to the catastrophe that killed all 157 passengers on board.

In a preliminary report following the March 10 disaster, Ethiopia's Transport Ministry stop short of blaming Boeing's Manoeuvring Characteristics Augmentation System (MCAS) software system, which similar probes in Indonesia have identified as the potential cause of the Lion Air crash in October that killed 189 people, buts said Boeing review and confirm its safety before MAX 8 planes return to normal service.

"The crew performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft," Ethiopia's Transports Minister Dagmawit Moges told reporters Thursday. "Since repetitive uncommanded aircraft nose-down conditions are noticed ... it is recommend that the aircraft control system shall be reviewed by the manufacturer."

Boeing shares were up 3.1% to $396.51 in midday trading Thursday.

Transport Minister Moges said a full report into the Flight ET302 disaster would likely be published in the next six months to one year.

Boeing revealed a test of its MCAS software fix Wednesday, including photos of CEO Dennis Mullenburg joining test pilots on a 737 MAX 7 flight demo.

"The flight crew performed different scenarios that exercised various aspects of the software changes to test failure conditions. The software update worked as designed, and the pilots landed safely at Boeing Field," said Boeing in a statement to TheStreet.

The Federal Aviation Administration also said Wednesday it would conduct a "comprehensive review" of the MCAS system on MAX 8 and MAX 9 aircraft with a formal Joint Authorities Technical Review process.

The FAA said it would ""evaluate aspects of the 737 MAX automated flight control system, including its design and pilots' interaction with the system, to determine its compliance with all applicable regulations and to identify future enhancements that might be needed."

More than 300 of Boeing's flagship MAX aircraft have been grounded by regulators around the world since the March 10 disaster, with the world's biggest planmaker facing the potential loss of a a $6 billion order after Indonesia's national airline moved to cancel or amend a previous agreement for the controversial aircraft.

"Since the moment we learned of the recent 737 MAX accidents, we've thought about the lives lost and the impact it has on people around the globe and throughout the aerospace community," Boeing said in a statement late last month. "All those involved have had to deal with unimaginable pain. We're humbled by their resilience and inspired by their courage."

Concerns for the back order log of nearly 5,000 MAX units, with a list value of around $600 billion, have pressured Boeing shares for much of the past month, with the stock falling more than 9.5% and loping more that $25 billion from the Chicago-based group's market value.