The problems from above are usually the result of an unofficial operation that you have applied on your Android device. Thus, in most cases you can experience issues after gaining root access, installing a custom recovery image, flashing a custom ROM firmware, removing bloatware or in built programs, installing a custom kernel and so on. Because of that I strongly recommending you to use only tested tutorials that are compatible with the model of your Android device, because else you can end up in bricking your phone; not to mention that when applying such operations the warranty of your phone will get void – because the binary flash of your device will be modified.
Now a hard reset does not represent a custom or risky operation. This feature is preinstalled on any Android device and you can also perform it in two ways: by using your phone menu or by using a combination of volume up / down and power buttons – I will explain both methods to you in a minute. So, you will not use custom apps in order to hard reset your HTC One. Don’t worry as the process is quite easy and as you will see the same can be applied even by a newbie.
Since a hard reset implies in wiping the internal system of your HTC One, the best will be to make a backup before doing anything else. Of course apply the backup only if you can still use your phone; else skip this part as there is nothing you can do in that matter. I recommend you to save everything that’s there on the internal storage memory of your device, including text messages, call logs, market apps, contacts list, internet settings and personal info, data and accounts. Don’t worry as the backup can be easily completed especially if you use dedicated and free distributed apps from Google Play.
Good; we are almost done. So, just remember that this tutorial is compatible only with the HTC One. Thus, don’t use the steps from below for making a hard or factory reset on a similar or different Android based device. Moreover, this procedure has been tested on the HTC One, so you can be sure that the steps from below will work properly.
How to Hard Reset HTC One
Hard reset using fastboot mode
Take your phone (you can turn it off or you can use it while is still running) and press volume down and home buttons at the same time.
Press these buttons until the screen goes black.
When that happens, release the power button but don’t release the volume down key.
Keep pressing the Volume down button until fastboot mode is being displayed.
In fastboot use volume up and down buttons in order to scroll up or down.
Enter recovery mode.
Choose “factory reset” option and press power button to select.
Agree and perform the hard reset operation.