Mate 8 - 3g/4g Sim Card Slot - "Locked"? - Summarized

Firstly let me apologize for duplicating the content of several other topics. This post will intend to summarize the issue in order to provide better visibility to anyone trying to help.

To start off, I have the same problem with my Mate 8.

The Issue
The Huawei Mate 8 has two Sim Card Slots: one supports 3g/4g and the other supports only 2g. That's how it's build.
When you pun in non-China Telecom card into *either* of the slots a message pops up saying that 3g/4g is only supported on China Telecom: https://tj6nvw-bn1306.files.1drv.com...%29.png?psid=1


More Details

• It is possible to change the active 3g/4g card slot via settings configuration.


• You can use 2g capabilities in *any* of the physical slots (via configuration above)


• When you insert 2 sim cards only one of them is active. The device does *not* recognize the second card. It is possible to switch between the two cards, but only one of them can be active.

What is tried already?

• I've tried and confirm all the items above.


• Did factory reset.


• I've loaded the International Software to Mate 8 from this topics


• The Chinese Telecom message no longer appears on the International Software, however the slot still doesn't work.


• Did factory reset on the international Software as well.


• Tried to unlock it via DC-Unlocker - it is not possible. The "Unlock" button is grayed out.


• The Sim Status in DC-Unlocker is "unlocked" however it shows only one IMEI number, where the phone has 2 IMEI numbers if you check it via *#06#


• Guys report the same problem with Verizon cards, where Verizon and China Telecom networks are similar.

Thoughts/Suggestions
I talked to the DC Unlocker guys from the support and they advised me it might be from the Firmware. Even I've installed the international one and don't rule out that this might be the root issue of the issue as I don't know the origins of the International software.

Any suggestions?

Download from this link