Just FYI - when upgrading from version 23 to 25.12.2, I performed the listed steps referenced in the Release Notes (which were successful). I then performed the force sysupgrade and observed the following:
Flashing the sysupgrade file again solved the problem.
I also observe this in the log currently:
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.077500] ------------[ cut here ]------------
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.082111] WARNING: CPU: 0 PID: 1 at 0xc0002fc0
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.086714] Modules linked in:
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.089767] CPU: 0 UID: 0 PID: 1 Comm: swapper Not tainted 6.12.74 #0
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.096192] Hardware name: Meraki MX60/MX60W Security Appliance APM821XX 0x12c41c83 PowerPC 44x Platform
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.105635] NIP: c0002fc0 LR: c0002ee0 CTR: c0013d20
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.110672] REGS: c10359c0 TRAP: 0700 Not tainted (6.12.74)
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.116486] MSR: 00029000 <CE,EE,ME> CR: 24000442 XER: 20000000
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.122665]
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.122665] GPR00: c0008200 c1035ab0 c1050720 00000000 3e039bf6 00000018 01f01cdf 00000004
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.122665] GPR08: 0000000f 00000000 00000510 c1035b20 c0013084 00000000 c000230c 00000000
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.122665] GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.122665] GPR24: 00000000 c1303810 dfb9544c c09e0000 c13a2b28 00001000 e127c000 c1035b30
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.157484] Call Trace:
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.159921] [c1035b00] [c0008200] 0xc0008200
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.164179] [c1035b20] [c0000a30] 0xc0000a30
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.168438] --- interrupt: 600 at 0xc0013084
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.172698] NIP: c0013084 LR: c0082e84 CTR: 0000007f
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.177727] REGS: c1035b30 TRAP: 0600 Not tainted (6.12.74)
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.183541] MSR: 00029000 <CE,EE,ME> CR: 44000442 XER: 20000000
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.189720] DEAR: e127c020 ESR: c1076268
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.189720] GPR00: 00000007 c1035c20 c1050720 e127c000 00000000 00001000 e127c01c 00000004
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.189720] GPR08: 00001000 0000007f 00000cb3 00000000 24000248 00000000 c000230c 00000000
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.189720] GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.189720] GPR24: 00000000 c1303810 dfb9544c c09e0000 c13a2b28 00001000 e127c000 c1303810
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.227044] --- interrupt: 600
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.230086] [c1035c20] [c0082e08] 0xc0082e08 (unreliable)
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.235468] [c1035c60] [c0081c10] 0xc0081c10
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.239727] [c1035ca0] [c0513fec] 0xc0513fec
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.243986] [c1035cd0] [c04843b0] 0xc04843b0
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.248247] [c1035cf0] [c04813d8] 0xc04813d8
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.252506] [c1035d20] [c0481974] 0xc0481974
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.256766] [c1035d50] [c0481c14] 0xc0481c14
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.261025] [c1035d70] [c047e9f0] 0xc047e9f0
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.265285] [c1035da0] [c04802fc] 0xc04802fc
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.269544] [c1035dd0] [c0482958] 0xc0482958
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.273804] [c1035df0] [c092a434] 0xc092a434
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.278063] [c1035e40] [c0002594] 0xc0002594
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.282322] [c1035eb0] [c090cfec] 0xc090cfec
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.286582] [c1035ee0] [c000232c] 0xc000232c
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.290841] [c1035f00] [c000c1f8] 0xc000c1f8
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.295102] --- interrupt: 0 at 0x0
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.298583] Code: 480123c5 2c030000 4082ff84 80010054 38600001 83e1004c 38210050 7c0803a6 4e800020 38a00000 3920fff2 4bffff88 <0fe00000> 4bffffc4 80010054 7c0803a6
[Mar 30, 2026, 3:40:10 AM UTC] kern.warn: [ 4.313280] ---[ end trace 0000000000000000 ]---
I performed another flash, and this occurred again. This time, there was no network connectivity (meaning I need to proceed with serial recovery). I thought this issue was resolved with the MX60's.
I'll provide another update after I locate my serial adapter.