Four years since John's original post, I have the same issue - this time installing iOS 11 beta 2 on an iPhone 7 Plus. Also saw the "Searching" issue (whilst running on iOS 11 beta 1) a few days before updating. Strangely, now my device is bricked, when I try to restore the iOS 10.3.3 IPSW iTunes spits out error no. 52, only the iOS 11 IPSW shows error no. 3 - strange! Here are the last lines of my death logs: (clearly also a baseband issue 😟)
Restoring iOS 11 beta (error 3)
[22:32:40.0002] ==== end of device restore output ====
[22:32:40.0403] AMRAuthInstallDeletePersonalizedBundle
[22:32:40.0486] <Restore Device 0x60800034db50>: Restore failed (result = -1)
[22:32:40.0514] AMRestorePerformRestoreModeRestoreWithError failed with error: -1
[22:32:40.0514] Finished RestoreOS Restore Phase: Failed
[22:32:40.0515] State Machine Dump, status:ERROR - [state:Recovery remaining-cycles:0] -> [state:RestoreOS remaining-cycles:0 (current state)]
[22:32:40.0519] Changing state from 'Restoring' to 'Error'
[22:32:40.0519] State is now set to error
[22:32:40.0523] Restore completed, status:3
[22:32:40.0523] Failure Description:
[22:32:40.0523] Depth:0 Code:-1 Error:AMRestorePerformRestoreModeRestoreWithError failed with error: -1
[22:32:40.0523] Depth:1 Code:-1 Error:Failed to handle message type StatusMsg
[22:32:40.0523] Depth:2 Code:-1 Error:failed to update device firmware
[22:32:40.0523] Depth:3 Code:-1 Error:ramrod firmware update failed
[22:32:40.0523] Depth:4 Code:1004 Error:update_baseband: failed to perform next stage
[22:32:40.0523] Depth:5 Code:3 Error:Fail to ping baseband: kBBUReturnIOError
Restoring iOS 10.3.3 (error 52, same device, same setup!)
[17:02:33.3888] ==== end of device restore output ====
[17:02:33.4067] AMRAuthInstallDeletePersonalizedBundle
[17:02:33.5321] <Restore Device 0x6080003461a0>: Restore failed (result = -1)
[17:02:33.5347] AMRestorePerformRestoreModeRestoreWithError failed with error: -1
[17:02:33.5349] Finished RestoreOS Restore Phase: Failed
[17:02:33.5349] State Machine Dump, status:ERROR - [state:Recovery remaining-cycles:0] -> [state:RestoreOS remaining-cycles:0 (current state)]
[17:02:33.5354] Changing state from 'Restoring' to 'Error'
[17:02:33.5354] State is now set to error
[17:02:33.5358] Restore completed, status:52
[17:02:33.5358] Failure Description:
[17:02:33.5358] Depth:0 Code:-1 Error:AMRestorePerformRestoreModeRestoreWithError failed with error: -1
[17:02:33.5358] Depth:1 Code:-1 Error:Failed to handle message type StatusMsg
[17:02:33.5358] Depth:2 Code:-1 Error:failed to update device firmware
[17:02:33.5358] Depth:3 Code:-1 Error:ramrod firmware update failed
[17:02:33.5358] Depth:4 Code:1004 Error:update_baseband: failed to perform next stage
[17:02:33.5358] Depth:5 Code:52 Error:Fail to create transport kBBUReturnFailCreateTransportInitial
Still in warranty, so no way I'm going in the deep freeze 😉 Speaking with an Apple engineer (Simeon) to see what can be done.. I'll update if there is any generally useful info made available, but after four years I'm not holding my breath!