Boba crew says (based on Wiki): "After performing an attack, if the defender was dealt a faceup Damage card, you may discard this card to choose and discard 1 of the defender's Upgrade cards."

Chewie crew says: "When you are dealt a Damage card, you may immediately discard that card and recover 1 shield. Then, discard this Upgrade card."

Having in mind the rule to do what card says nothing more, how do you think, is Chewie preventing Boba from triggering? Chewie effect is fully resolved before Boba triggers, however this does not mean that the defender WAS dealt a faceup damage card. Though, it was already discarded.

English is not my first language, so I may lose some meaning, however, just looking at the working of both cards it seems that Boba does not care if the face up card is still there or not (otherwise, those crits that are dealt, triggered and flipped would be painful for Boba)...

What's your opinion? Or maybe I have missed this discussion and the question was already answered?

Thanks in advance for your help!

Boba only cares that the card was dealt initially, not what happens to it afterwards. So, Chewie crew or Integrated Astromech could discard it, Chewie pilot could flip it facedown (or it could flip itself like Thrust Control Fire or Major Explosion) it doesn't matter.

All that matters is that the card was initially dealt face up.

However, it's possible that you could deal the card which would allow you to trigger BOba, and that by discarding the card, the target ship might have also discarded all its upgrades, so BOba wouldn't have anything left to work on - e.g. you hit an x-wing, dealing a faceup card. It discards Integrated Astromech and its R2 unit... and now it has no upgrades left, so BOba can't forcibly discard one.

Ninjd and our first sentences are the same.

Boba only cares that the card was dealt, not what happens to it afterward. Chewbacca does not stop Boba.

Repeating this again.

Boba crew only cares that an attack deals a face-up card. What happens to that card afterwards doesn't matter because Boba can still go after an upgrade. Now if the card is dealt face-down and something else turns it face up then Boba would not trigger.