How to get into Service Mode with my Samsung Galaxy S-core (SM-G350)?

[robse94]

Im trying to get into service mode so i can set my frequency band settings, as i bought my phone in europe and T-mobile US uses a band frequenzy here for 4g wich is used in europe for edge.-> Can't get 4g.
Tried all these code-> didnt work. Phone is rooted

Need help pleeeease!

 

[Rukbat]

*#0011# or *#0*# or *#2263#

I don't know if you'll be able to change the frequency/function pairing, though - no matter what menu you get into.

 

[robse94]

OK, see what I'm trying to do is what this guy does:
androidforums.com/threads/how-to-enable-850mhz-3g-network-frequency-on-your-samsung-i9000-galaxy-s.258859/
In germany the 1900 frequency is used for 2g, in the US T-mobile uses it for 4g. I want to change that so i can get 4g.
i get into some kind of service mode with *#0011# but I cant access to the band settings like the guy in the link before. I think that only works with jelly 4.1.1.
So my question is how can I change these settings in 4.2.2???