Last Modified: Nov 06, 2026
Affected Product(s):
F5OS F5OS-C
Known Affected Versions:
F5OS v2.0.0, F5OS v2.0.0-HR1, F5OS v2.0.0-HR2, F5OS v2.0.0-HR3, F5OS-C 1.8.2, F5OS-C 1.8.2-HR1, F5OS-C 1.8.2-HR2, F5OS-C 1.8.2-HR3
Opened: Jul 06, 2026 Severity: 2-Critical
BX520 blades can reboot under certain traffic loads. The signature for this bug being the cause of the reboot is a "pin reset" message in the pel log: 08/04/2026 15:08:28 | 21981 | AOM | 255 | Na | 6 | AOM boot marker (v1.00.231.0.1) 08/04/2026 15:08:28 | 21982 | AOM | 255 | Na | 6 | pin reset 08/04/2026 15:08:28 | 21983 | AOM | 255 | Na | 6 | power-on reset
Blade(s) reboot causing a traffic disruption.
Any VELOS chassis using BX520 blades and under traffic load.
The following workaround disables Turbo Boost functionality both temporarily and persistently across system startups. The procedure must be repeated on all blades. If a blade is PXE-booted or replaced via RMA, the configuration will not persist. In such cases, you will need to reapply these steps to disable Turbo Boost. This change lowers the CPU clock speed under load, reducing throughput and increasing latency, which leads to a drop in performance Steps to Disable Turbo Boost 1. Disable Turbo Boost immediately. echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo 2. To disable Turbo Boost on blade startup, create a tmpfiles.d configuration file with the following command (requires root privileges): echo "w /sys/devices/system/cpu/intel_pstate/no_turbo - - - - 1" > /etc/tmpfiles.d/disable-turbo-boost.conf Verification Steps to Confirm Turbo Boost is disabled v1. Confirm the Max CPU frequency reflects a non-Turbo state. cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq Expected output: 2200000 v2. Validate Turbo Mode Status. cat /sys/devices/system/cpu/intel_pstate/no_turbo Expected output: 1, indicating that Turbo Boost is disabled
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