P.S. Here is a copy of one of our update logs that iTunes optionally sends back to Apple when a failure occurs, etc. (We let several of these be sent in) There are several errors near the end, including an "Internal error"
iPodUpdater 1 2015-01-01.log
2015-01-01 21:42:12.948 [7316:1c4c]: restore library built Oct 7 2014 at 14:24:11
2015-01-01 21:42:12.948 [7316:1c4c]: iTunes: iTunes 12.0.1.26
2015-01-01 21:42:12.948 [7316:1c4c]: iTunes: Software payload version: 12B440
2015-01-01 21:42:12.948 [7316:1c4c]: iTunes: Using MobileRestore state machine
[02:42:23.0846] Changing state from '(null)' to 'Restoring'
[02:42:23.0846] requested restore behavior: Erase
[02:42:23.0861] requested restore behavior: Erase
[02:42:23.0861] requested variant: Erase
[02:42:23.0861] requested restore behavior: Erase
[02:42:24.0532] amai: _AMAuthInstallBundleCreateServerRequestDictionary: withApTicket is True
[02:42:24.0532] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "RestoreLogo" Digest = "<CFData 085DB3E0 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "RestoreDeviceTree" Digest = "<CFData 085DB938 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "RestoreKernelCache" Digest = "<CFData 085DB6B0 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "RestoreRamDisk" Digest = "<CFData 085DB308 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "iBEC" Digest = "<CFData 085DB278 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "iBSS" Digest = "<CFData 085DB350 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "KernelCache" Digest = "<CFData 085DB110 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: entry "ftap" not part of manifest, skipping
[02:42:24.0548] amai: _AMAuthInstallBundleCreateServerRequestDictionary: entry "rfta" not part of manifest, skipping
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: entry "ftsp" not part of manifest, skipping
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: entry "rfts" not part of manifest, skipping
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "BatteryCharging0" Digest = "<CFData 085DB1A0 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "BatteryLow1" Digest = "<CFData 085DB7D0 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "AppleLogo" Digest = "<CFData 085DB4B8 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "DeviceTree" Digest = "<CFData 085DB5D8 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "BatteryCharging1" Digest = "<CFData 085DB668 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0563] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "BatteryPlugin" Digest = "<CFData 085DB740 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0579] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "LLB" Digest = "<CFData 085DB428 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0579] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "iBoot" Digest = "<CFData 085DB1E8 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0579] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "BatteryFull" Digest = "<CFData 085DB470 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0579] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "RecoveryMode" Digest = "<CFData 085DB500 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0579] amai: _AMAuthInstallBundleCreateServerRequestDictionary: personalizing "BatteryLow0" Digest = "<CFData 085DB6F8 [7253907C]>{length = 20, capacity = 20, bytes = 0x<<<<<<<<<<<<<<<<<<UDID>>>>>>>>>>>>>>>>>>}"
[02:42:24.0579] amai: _AMAuthInstallBundleCreateServerRequestDictionary: using UniqueBuildID <CFData 085AD430 [7253907C]>{length = 20, capacity = 20, bytes = 0xb4a53a00140f136ddf267a31b6d37652a4452586}
[02:42:24.0579] amai: AMAuthInstallRequestSendSync: SSO function returned NULL and no SSO token was provided, SSO disabled.
[02:42:24.0704] amai: tss_submit_job: HttpEndRequest failed=12031
[02:42:24.0704] amai: AMAuthInstallRequestSendSync: failed tss submission: Internal error
[02:42:24.0704] amai: AMAuthInstallApCreatePersonalizedResponse: server request error: Internal error
[02:42:24.0704] amai: AMAuthInstallBundlePersonalizePartial: failed to create ap ticket
[02:42:24.0719] failed to personalize the restore bundle: Internal error
[02:42:24.0719] AMRAuthInstallDeletePersonalizedBundle
[02:42:24.0782] Restore completed, status:3014
[02:42:24.0782] Failure Description:
[02:42:24.0782] Depth:0 Error:Failed to copy preflight options during recovery mode restore.