The thing is it that it is much easier to hack rewards..
So go into the expedition mode.
Look at all the rewards, look for them as a group search.
for example, you can search for 60;8000 (Dword) (last gem and gold rewards for stage 1)
then you can continue to filter with searches, or you can slightly change half of the numbers, close expedition mode, open it back again and see if anything`s changed. filter you list again.. repeat.. until you get one right address (dont forget to leave expedition mode and go back again too look for changes)
Once you have at least one right address (for a reward) you can look at the adress list (long press, go to the adress option) and find the others.
Once you got the addresses you can change the reward value (and the reward itself, changing the address right above the quantity)
(I tried a few values and got this: 1=gold; 2=gems; 60=card; 30=chest; 25=golden chest; 40=golden key; 41=silver key; 61=card pack; 62=hero card)
then play and get the rewards