Otherwise, you’ll just have to wait until an update to the app is released that works with Marshmallow. If you really need to use FoxFi on Marshmallow, you can try one of the workarounds. However, this will void your warranty and may cause other problems. The easiest workaround is to root your phone and disable Verified Boot. There are some workarounds that allow you to use FoxFi on Marshmallow, but they are all somewhat complicated and may not work on all phones. Since Verified Boot now prevents modified system images from booting, FoxFi no longer works on Marshmallow.
FoxFi modifies the system image to add the functionality to use the phone as a Wi-Fi hotspot. If Verified Boot finds that the system image has been modified, it will refuse to boot the phone.
Verified Boot checks the integrity of the Android system image before it is loaded and verifies that it has not been tampered with. The reason for this is that Marshmallow introduced a new security feature called “Verified Boot”. However, since the release of Android 6.0 Marshmallow, FoxFi has stopped working on many phones. The app has been around for a while and it used to work on all Android phones. FoxFi is an app that allows you to use your Android phone as a Wi-Fi hotspot without incurring any additional charges from your carrier.
