To unlock all of them, you have to make all the 3 last endings. if you'll unlock one or two it won't give you anything until you complete the 3 endings. you dont have to replay the campaign, just repeat the last mission again.
3 choices is one to give to the girl. one to the guy and one doing nothing.
Ok, i couldn't find the right fix. but i got some ideas.
First i check, and many people who had this problem decided to kill Irish first for the m249.
and after that they couldn't continue to get p90 and the other gun.
Before you do anything
Trying playing one game on the multiplayer and check again the assignments. Someone said that this fixed his problem.
Now. in my opinion (not sure if its gonna work..)
Try removing the saves and options in My Documents > Battlefield 4 delete the folder. (it should reset your campaign, so, only if you really want the P90 you'll have to do that).
Now try playing the game (suggesting on hard (for fun sake 😉) until you complete it.
And now. try choosing hannah for the first time. then irish and then nothing (this is was the way i did it)
I thought about that, because any movement you do can trigger any bug.
