Both accidents were down to flaws in the flight control systems on the 737 Max aircraft which caused nosedives.
Boeing was found to have failed to disclose information about the system but avoided a trial by agreeing to pay $2.5bn (£1.8bn) in fines and compensation.
Relatives of those who died are trying to reopen the settlement.
It means that for the first time, the company will be formally charged in court in relation to the two crashes, and will have to plead guilty or not guilty.
