IOS 12 has been running fine on my ipad pro. This morning when I picked it up, I found it in a continuous loop, rebooting to the apple logo screen over and over. The only way to access itunes is in DFU mode. Here I have tried starting both update and restore using ios 12 initially, then trying ios 11.4. The process starts and reaches the "Waiting for Ipad" phase. Apple logo with a blank bar below appears on the ipad screen for about a minute. Then itunes generates and error dialog: "This iPad "iPad" could not be restored. An unknown erro occurred (9)."
I have tried switching computers running different copies of OS X and itunes, changed cables, cleaned out the charging port. Nothing has worked so far. I'm looking for addtional suggestions on how to resolve this issue.
Thanks in advance.