Boeing upgrades software on crisis-hit 737 MAX after deadly crash

Boeing is upgrading the stall prevention software on its 737 MAX, industry sources said Friday, as French investigators scoured black box data from the latest of two deadly crashes involving the aircraft in recent months.The MAX has been grounded worldwide following Sunday's Ethiopia Airlines disaster that killed all 157 on board, and the fallout has left the company, regulators and airlines scrambling to respond.Boeing will fine-tune its MCAS system -- implicated in the crash of a Lion Air 737