Hi, I have a very specific problem with the data connection. I am using the Note 5 dual sim variant which I want to use solely for my business uses; one local Hong Kong sim card (SmarTone) and one USA sim card (T-mobile) for international calls (cheaper). Local sim card to make local calls and internet; USA sim card to use only for calls. Now, the problem is that when ever I enable the T-mobile, data connection from HK sim drops and it seems to be using data from T-mobile, which does not have internet. This is even if I already chose data preference to HK sim in the SIM card manager. I will need to disable the T-mobile AND restart to use internet from HK sim again. It seems like the SIM card manager doesn't do its job because I also set voice call and sms preference to HK sim, but I still need to pick the sim to make call/sms every time, although annoying but not very crucial. The very strange thing is that when I put in other local number instead of T-mobile (I put in China Mobile HK), the problem doesn't occur (ie. I can still use internet from SmarTone sim) I went to service centre and apparently they have no clue of what's going on. One thing to note is that, they tried putting both of my SIMs using another Note 5 in the centre, and it works with no data problem (voice call and sms preference doesn't work as the case of my phone, however). The main difference is that my phone already updated to Android 6, but the centre's hasn't. Note that I didn't try using both sim before updating to Andriod 6. I do have more faith in online community than in the Samsung service centre, so please help me out.