Update on Aug, 1st: Apple releases fourth iOS 12, tvOS 12, and macOS Mojave public betas, the firmware is iOS12beta5 in 3uTools .
Happy beta release day — iOS 12 developer beta 5 is out now. iOS 12 is getting closer to being complete with the release expected around early September, so we’ll dig in and see if anything has changed in the new version.
Operations
Step 1 Connect your iDevice to PC with genuine USB cable and launch 3uTools. You are recommended to back up your device before any changes.
Step 2 Navigate to Flash & JB → Easy Flash, select the iOS 12.0beta5 firmware. If you want to save data, please click the checkbox “Retain User’s Data While Flashing”. Click “Flash” to start downloading iOS 12 beta 5.
Step 3 Please do not disconnect your iDevice and wait patiently until the process is finished, it would probably take 5 to 10 minutes. And after that, your device will be restored to iOS 12 beta 5.