i have 3 galaxy phone please tell me ho to recover
 

1st=galaxy s2 i9100 null imei.three time successful repair with z3x but after restart again imei null.
2nd=galaxy s4 hang on galaxy s4 logo with kernal is not seandroid enforcing error.i try to flash with 4.3 and 4.2.2 full version but odin 3.09 and 3.07 always give a error.odin successfull flash only one tar file but error is still.
3rd=galaxy s4 i9506 network problem.after write efs with z3x imei corupt no imei show /01.now i try to root this methad
How to Root Galaxy S4 (LTE+) I9506 on Android 4.3 Jelly Bean - Android Forums at AndroidCentral.com
but z3x alwways says try to manuly root.please expert help me.

S2 i9100 actually null problem basband problem must change basband chip

S4:i9505 first you check efs if goood when flash with this file same I9505XXUGNE5_OJVFNE1_XSI_United Arab Emirates_4.4.2_KitKat and Odin3_v3.09 use this if same problem maybe inside problem

s4 i9506 bro change different firmware update