Download Impactor. Download yalu beta 3. Connect your device to your computer. Drag yalu beta 3 to Impactor. Sign with Apple ID using App Specific password if you have that enabled. Reboot phone. Cydia and mach_portal should be on home screen. Go into Settings, General, Profiles & Device Management, Verify mach_portal app. Launch mach_portal app. After app launches and closes itself on its own without rebooting the phone (It may fail and reboot the phone, it doesn't always work on the first try. You just have to be persistent until it succeeds.) Launch Cydia, add repo: http://83.218.67.215/~ijapija00/cydia/ and download Substrate Fix (iOS 10) and use that to Respring the device whenever necessary. Never click on Respring from within Cydia. Click on the Substrate Fix app on the home screen and your phone will reboot into a jailbroken state. A cog wheel will show the whole reboot time if it succeeded. If not, the phone failed and is rebooting. You simply have to run the mach_portal app again until it succeeds and run Substate Fix again. I found that it succeeds better when fully turning off the device after a fail and turning it back on before trying again. It may not really help, but it's what I do.