macOS 27 beta: every OS update fails — MobileSoftwareUpdate 1259 "failed to copy firmware identity" (orphaned iSCPreboot volume-group dir) — FB24342236

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Created 2w

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Every macOS update fails during preflight personalization on my MacBook Pro (Mac15,6, Apple Silicon), currently on 27.0 build 26A5378j. It's failed on every build from beta 5 (26A5406e) through beta 7. Identical failure via Software Update and via startosinstall. It fails LOCALLY, before contacting Apple (gs.apple.com and gdmf.apple.com are both reachable with valid certs).

Error (install.log + unified log):

reaches PREFLIGHT_PERSONALIZE (~0.15), then aborts
MobileSoftwareUpdateErrorDomain Code=1259 "failed to copy firmware identity"
"could not obtain device identity information through SFR installer"
SUMacControllerErrorPreflightPersonalizeFailed=7723

Root cause I've traced: an orphaned volume-group boot-policy directory in /System/Volumes/iSCPreboot/. ls shows two volume-group UUID dirs — the live one (matches diskutil info /) and an orphan (3D3287DE-...) with no corresponding APFS volume group (diskutil apfs list shows only one live group). Both date to Feb 2024. The preflight can't reconcile the System Recovery boot policy in the orphaned dir.

Note: NOT caused by Erase All Content and Settings (unlike the commonly reported case). The orphan predates the beta, so any pre-existing second volume-group boot-policy directory reproduces it. It was harmless for ~2 years; macOS 27's stricter preflight rejects it.

Ruled out (no effect): disk space, VPN, DNS, clock, Apple Account, refreshing the beta seed entitlement, reboot, Time Machine, re-downloading the installer, and Recovery reinstall (same 1259).

Filed as FB24342236 — no response across beta 5, 6, 7.

Questions:

Is this a known issue with a planned fix, and in which build?
Any supported recovery path that does NOT require a second Mac? (Recovery reinstall fails the same way.) Or is DFU Revive/Restore the only option?
Will the public 27.0 release install on this machine, or hit the same preflight?

Answer 1

mrauhecker OP

2w

markusrauhecker@MARKUSs-MacBook-Pro-2 % softwareupdate --history Display Name Version Date

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

Answer 2

mrauhecker OP

2w

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.