Guitar Tuned down half step (Eb) 

verse: 
eb--------------------------------- 
Bb--------------------------------- 
Gb--------5------7------3---------- 
Db--------5------7------3---------- 
Ab--------3------5------1---------- 
Eb--------------------------------- (x2) 

last time before chorus (third time playing riff): 
eb-------------------------------------- 
Bb-------------------------------------- 
Gb--------5------7------3--------------- 
Db--------5------7------3---------5----- 
Ab--------3------5------1---------5----- 
Eb--------------------------------3----- 

chorus: 
eb------------------------------------------------- 
Bb------------------------------------------------- 
Gb--------5------9------3-------------------------- 
Db--------5------9------3----------3----2----3----- 
Ab--------3------7------1----------3----2----3----- 
Eb---------------------------------5----3----1----- (x3) 

last time before verse (4th time playing chorus riff): 
eb---------------------------------------------------- 
Bb---------------------------------------------------- 
Gb--------5------9------3----------------------------- 
Db--------5------9------3----------3----2----3---5---- 
Ab--------3------7------1----------3----2----3---5---- 
Eb---------------------------------5----3----1---3---- 

the 2nd verse is only half as long as the first... 
so instead of playing verse2 (x2) just play is once. 
It's that simple!