I had the problem too. After a few attempts at a soft reset, I contacted support. Since I had all the data in the cloud, I was also ready to use a hard reset or backup. And with that it worked. Start iTunes and connect iPad Mini 5 to the computer iPad restarted with Power + Home At the Apple logo just hold Home button until the recovery mode is displayed The computer should now recognize the iPad and display a message that an error was detected with the update and a new update must be loaded iTunes loads iPadOS 15.0.2 - Again, an error was detected after the update was applied iPad Restore - Last backup selected and installed After the backup was set up again I had a working iPad Mini 5 with stable iPadOS 15.0.2. Hope it helps you.