Cisco APIC Installation and ACI Upgrade and Downgrade Guide

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Cisco APIC Installation and ACI Upgrade and Downgrade Guide

Switch upgrades

Updated: July 12, 2026

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Explains the process of upgrading network switch firmware and software components.

A switch upgrade is a network maintenance process that

  • updates the firmware, software, or hardware components of network switches

  • enhances functionality, security, and performance of the network infrastructure, and

  • ensures compatibility with newer network protocols and features.

Switch upgrade summary information

The following sections provide a detailed summary of switch upgrades.

How ACI switch upgrade and downgrade stages work

During an ACI switch node upgrade or downgrade, the upgrade or downgrade progress will advance based on the stages which have completed.

Summary

The key components involved in the ACI switch upgrade and downgrade process are:

  • APIC: Downloads firmware to the switch and initiates the upgrade process

  • Switch: Receives firmware, extracts images, updates software components, and performs reboot

  • Bootflash: Storage component that is checked and validated during the upgrade

  • EPLD and BIOS: Hardware components that are upgraded during the process

  • Fabric: Network infrastructure that the switch rejoins after successful upgrade

Workflow

These stages describe how the ACI switch upgrade and downgrade process progresses:

  1. At 0% progress, firmware upgrade is queued and firmware is downloaded to the switch from the APIC.
  2. At 5% progress, firmware upgrade begins and the upgrade installer is initiated.
  3. At 45% progress, bootflash check completes and image extraction stage begins.
  4. At 60% progress, image extraction stage completes and the grub partition is updated with new software information.
  5. At 70% progress, the software has been updated on the switch.
  6. At 80% progress, EPLD and BIOS upgrade begins.
  7. At 95% progress, EPLD and BIOS upgrade completes and switch reboot is initiated.
  8. At 100% progress, upgrade is successful and the switch rejoins the fabric after clean reload running target version of software.