It has been reported by some that Huawei Mate 9 won’t rotate and gyro or accelerometer has stopped working. This issue is happening when the screen rotation is activated and turned on. This means that the Mate 9 screen doesn’t rotate even on the Internet page and is stuck in the vertical and won’t go horizontal when the camera is moved.
Other common issues that have been facing the Mate 9 is that the default camera is showing everything upside down (ie, inverted) also all the Mate 9 buttons are upside down. If none of the methods below work, there could be a software bug problem with the current software and it’s suggested to update the Mate 9 to the latest software.
There can be two ways to fix the Mate 9 screen rotation problem; the first recommendation is to hard reset  the Mate 9.
An effective method to check if the phone’s gyroscope or accelerometer is functioning by doing a self-test. This will help to see what the real issue is when the Mate 9 screen won’t rotate. You can do this by pressing the code “*#0*#” (without the quotation marks) on the Mate 9 dial pad. Once you are in the service mode screen, tap on “sensors” and do a self-test.
If your wireless carrier disabled the option to access the service screen, then your only recourse here is to reset the phone to its factory defaults . To learn how to factory reset the Mate 9, read this guide . It’s also recommended to check this issue with your service provider first though as they may know by now that the problem exists and have some solution for you.
Another out-of-the-box tip from some that we don’t suggested doing is hitting the Mate 9 with the back of your hand to give your phone a gentle jolt. If you want to take the risk, you may want to do that, just be careful. Again, the most recommended way to fix when the Mate 9 screen wont rotate is to complete a hard reset. It’s important to note that doing a Huawei Mate 9 hard reset, this process will remove and delete all data, apps, and settings. You should back up your Mate 9 to prevent any data from being lost. The way to back up data on your Mate 9 is by going to Settings > Backup & reset. You can learn how to perform a hard reset on the Mate 9 with this guide, here .