UPDATE — still failing on the current beta (build 26A5421a), reproduced [DATE]. No change: identical PREFLIGHT_PERSONALIZE / MobileSoftwareUpdate Code=1259 "failed to copy firmware identity" abort as originally reported. REGRESSION PINPOINT (from softwareupdate --history): This Mac installed every macOS update cleanly for ~2.3 years — from Sonoma 14.4 (Mar 2024) through macOS 27 Beta 3 (build 26A5378j), installed 2026-07-08. Beta 3 is the LAST macOS update that ever succeeded here. The FIRST failure was the next build, macOS 27 Beta 4, and every OS update since has failed identically — Beta 4, 5, 6, and 7 (current build 26A5421a). The orphaned volume-group boot-policy directory in /System/Volumes/iSCPreboot/ (3D3287DE-280D-4619-AAAB-D97469CA9C71, with no matching APFS volume group) predates all of this — it dates to Feb 2024 and was tolerated by the update preflight for 2+ years. Something in the macOS 27 preflight between Beta 3 and Beta 4 began rejecting it. This presents as a preflight regression introduced at Beta 4, not a change in state on my end. CONFIRMING SIGNATURE: After Beta 3, the only successful installs in the history are "Command Line Tools for Xcode" (beta 5 and beta 6). Those are ordinary packages that do NOT perform firmware personalization, and they install fine. Only the macOS OS updates — which require the firmware-personalize step — fail. This isolates the failure precisely to firmware personalization (the SFR / device-identity step), consistent with 1259. Ref FB24342236.

markusrauhecker@MARKUSs-MacBook-Pro-2 % softwareupdate --history Display Name Version Date macOS Sonoma 14.4 14.4 03/10/2024, 06:20:36 macOS Sonoma 14.4.1 14.4.1 03/28/2024, 08:37:37 macOS Sonoma 14.5 14.5 05/22/2024, 13:14:13 macOS 15 Beta 15.0 06/11/2024, 18:19:52 macOS Sequoia 15 Beta 2 15.0 06/25/2024, 19:56:55 macOS Sequoia 15 Beta 4 15.0 07/30/2024, 18:18:36 macOS Sequoia 15.1 Beta 15.1 08/04/2024, 13:48:24 macOS Sequoia 15.1 Beta 2 15.1 08/14/2024, 01:48:04 macOS Sequoia 15.1 Beta 3 15.1 08/29/2024, 14:13:09 macOS Sequoia 15.1 Beta 4 15.1 09/20/2024, 15:05:57 macOS Sequoia 15.1 Beta 5 15.1 09/27/2024, 19:18:13 macOS Sequoia 15.1 Beta 6 15.1 10/11/2024, 14:23:04 macOS Sequoia 15.1 Beta 7 15.1 10/20/2024, 13:12:45 macOS Sequoia 15.1 15.1 10/25/2024, 09:09:09 macOS Sequoia 15.1 15.1 10/30/2024, 01:41:57 macOS Sequoia 15.2 Beta 2 15.2 11/06/2024, 14:06:19 macOS Sequoia 15.2 Beta 3 15.2 11/14/2024, 10:32:59 macOS Sequoia 15.2 Beta 4 15.2 11/27/2024, 21:49:51 macOS Sequoia 15.2 15.2 12/10/2024, 16:47:10 macOS Sequoia 15.2 15.2 12/12/2024, 21:01:09 macOS Sequoia 15.3 Beta 15.3 12/18/2024, 12:22:45 macOS Sequoia 15.3 15.3 01/26/2025, 20:50:41 macOS Sequoia 15.3.1 15.3.1 02/11/2025, 12:34:19 macOS Sequoia 15.4 Beta 15.4 02/23/2025, 20:00:40 macOS Sequoia 15.4 Beta 3 15.4 03/11/2025, 18:09:57 macOS Sequoia 15.4 Beta 4 15.4 03/19/2025, 00:18:00 macOS Sequoia 15.4 Release Candidate 15.4 03/29/2025, 16:03:15 macOS Sequoia 15.5 Beta 15.5 04/06/2025, 01:20:11 macOS Sequoia 15.5 Beta 2 15.5 04/15/2025, 12:52:05 macOS Sequoia 15.5 Beta 3 15.5 04/28/2025, 11:12:51 macOS Sequoia 15.5 Beta 4 15.5 04/29/2025, 20:32:26 macOS Sequoia 15.5 15.5 05/18/2025, 12:55:52 macOS 26 Beta 26.0 06/10/2025, 13:29:10 macOS Tahoe 26 Beta 2 26.0 06/24/2025, 13:12:49 macOS Tahoe 26 Beta 3 26.0 07/08/2025, 13:22:33 macOS Tahoe 26 Beta 4 26.0 07/25/2025, 10:34:13 macOS Tahoe 26 Beta 8 26.0 08/27/2025, 10:15:01 macOS Tahoe 26 Beta 9 26.0 09/05/2025, 22:49:07 macOS Tahoe 26 26.0 09/10/2025, 07:21:10 macOS Tahoe 26 26.0 09/19/2025, 10:48:32 macOS Tahoe 26.1 Beta 26.1 09/25/2025, 11:42:23 macOS Tahoe 26.1 Beta 2 26.1 10/09/2025, 09:19:22 macOS Tahoe 26.1 Beta 3 26.1 10/15/2025, 15:36:15 Command Line Tools for Xcode 26.0 26.0 10/19/2025, 19:51:36 macOS Tahoe 26.1 Beta 4 26.1 10/21/2025, 10:51:35 macOS Tahoe 26.1 26.1 10/29/2025, 20:41:58 Command Line Tools for Xcode 26.1 26.1 11/04/2025, 14:08:43 macOS Tahoe 26.2 Beta 26.2 11/09/2025, 12:44:46 macOS Tahoe 26.2 Beta 2 26.2 11/17/2025, 14:44:03 macOS Tahoe 26.2 Beta 3 26.2 11/19/2025, 23:07:58 macOS Tahoe 26.2 Release Candidate 26.2 12/05/2025, 00:25:47 Command Line Tools for Xcode 26.2 26.2 12/15/2025, 13:44:49 macOS Tahoe 26.3 Beta 26.3 12/16/2025, 09:43:39 macOS Tahoe 26.3 Beta 2 26.3 01/13/2026, 13:48:50 macOS Tahoe 26.3 Beta 3 26.3 01/29/2026, 11:31:00 macOS Tahoe 26.3 26.3 02/06/2026, 06:36:40 macOS Tahoe 26.4 Beta 2 26.4 02/24/2026, 11:53:39 Motion Supplemental Content 1.0 02/25/2026, 18:35:57 Final Cut Pro X Supplemental Content 1.0 02/25/2026, 18:35:57 Pro Video Formats 3.1 02/25/2026, 18:35:57 Command Line Tools for Xcode 26.3 26.3 03/06/2026, 08:49:01 macOS Tahoe 26.4 Beta 3 26.4 03/06/2026, 08:52:09 macOS Tahoe 26.4 Beta 4 26.4 03/14/2026, 10:44:47 Command Line Tools for Xcode 26.4 26.4 03/25/2026, 21:09:14 macOS Tahoe 26.4 26.4 03/27/2026, 02:50:39 macOS Tahoe 26.5 Beta 26.5 04/03/2026, 10:30:17 macOS Tahoe 26.5 Beta 2 26.5 04/15/2026, 14:03:41 macOS Tahoe 26.5 26.5 05/19/2026, 11:45:44 Command Line Tools for Xcode 26.5 26.5 05/19/2026, 17:17:34 macOS Tahoe 26.6 Beta 26.6 06/07/2026, 15:17:48 Command Line Tools for Xcode 27.0 beta 1 27.0 06/09/2026, 08:56:41 Command Line Tools for Xcode 27.0 beta 3 27.0 07/08/2026, 09:42:19 macOS 27 Beta 3 27.0 07/08/2026, 11:45:46 Command Line Tools for Xcode 27.0 beta 5 27.0 08/14/2026, 21:10:44 Command Line Tools for Xcode 27.0 beta 6 27.0 08/25/2026, 09:43:35 markusrauhecker@MARKUSs-MacBook-Pro-2 %