Can't WiFi tether on AT&T plan that allows it..

I am using my SIM from an iphone, and my stock device won't let me enable WiFi hotspot, telling me it needs to be enabled on my plan. The tethering worked fine on the iphone and the 3GB Mobile Share plan I am on says that it is permitted.

Do other people have this working? Is this because they don't have my proper IMEI attached to the SIM? Does AT&T have these IMEI numbers in their database or will I lose LTE if I update my IMEI?

Current Cricket customer, want to switch to MetroPCS unlimited data plan tethering?

I'm currently with Cricket Wireless. MetroPCS is advertising great speeds and with their unlimited plan, I was thinking about tethering my phone to my PC and using it's data plan and speeds for my PC. This way, it's cheaper than getting new Internet Service and I get to use my phone as well. Is it truly unlimited data and is there any limitations when it comes to tethering to PC? Do I need an add-on pack for that? Is it easy to do with any phone or would a certain phone be easier? I haven't purchased a phone yet so I will need to know which is best and if it will work! Thanks guys.

Sprint Open World Plan and rooted device

I have a rooted Sprint Samsung S6. Stock rooted.
I'm travelling to Canada soon and Chatted with a Sprint Agent about International Roaming. It's called Sprint Open World Plan.
I'm just checking to see if the following procedure will brick my phone for what ever reason:
Before leaving the US: Connect to WiFi and go to: Settings > System Update > Update profile.

Once you arrive, please apply these settings:
Settings > More Networks > Roaming > Roaming Settings > Turn on international Voice.

Settings > More Networks > Mobile Networks > Network Mode > GSM/UMTS > Select Manual.

You will then select: Rogers or TBayTel
thanks!

900FD data plan issue after 900FDXXU1CPF4 upgrade

Hello,
I updated my 900FD (XSG) from G900FDXXU1CPE1/CPB4 (mai 2016) to 900FDXXU1CPF4/CPB4 (june 2016) through OTA last week.
Since then I can no longer use data plan from sim2.
Configuration: French Sosh Sim1, French Bouygues Sim2

I tried both sim alone, regardless of slot 1 or slot 2: data plan OK
I tried both sim in a galaxy S6 (single sim): data access OK --> the sim cards are fine

The issue appears only if both cards are inserted, and Sosh card is in slot 1.
The issue is: data plan starts (or sometimes not) works for maximum 15s, and then stops.
I can't blame any operators, as sim cards and networks are fine, it's just the combination described above which fails !
I am using Sosh in slot 1 and Bouygues in slot 2 for the past 2 months without any issue (previous rom)...

I finally found that the Sosh card is NFC (NFC N9), whereas Bouygues card seems not to be NFC (nothing indicated).
NFC is off in the settings of the phone.

I am used to have personnal card in slot1 and Work card in slot2 for phone access, and don't want to try a firmware downgrade (downgrade may be risky).
Is anybody here have and idea how to sort out my issue ?

Regards,
Fred