Firmware Downgrade Rules for Cisco Small Business Switches
Objective
Cisco Small Business switches sold with the latest release of firmware 2.4.0.x and greater use an updated chipset for Power over Ethernet (PoE) 6920xM version 0x4a02. In addition to switches with this newer chipset, there are Cisco supported switches manufactured with firmware versions 2.2.8.4 to 2.4.0.x which use the 6920xM version 0x4b42 chipset. There are also switches manufactured with firmware versions 2.1.0.63 to 2.2.7.7 which use the 6920x version 0x4ac2 chipset.
Note: The "show power inline" command can be used in CLI to display the PoE chipset version. Switches manufactured with firmware 2.2.7.7 and prior are unable to display the PoE chipset version as part of the command output.
Due to the differences in chipset version support between the devices, refer to the below table for the firmware downgrade limitations per device.
Applicable Devices
Sx250 Series Switches
Sx350 Series Switches
Sx550 Series Switches
Software Version
2.1.0.63 and greater
Firmware Downgrade Rules
Device Name
Downgrade Rules
All non-PoE switches and switches with firmware 2.2.2.7 and below
Will follow the same downgrade rules as previous versions (Firmware can be downgraded down to the earliest version available for each SKU)
Sx250 series switches manufactured with firmware 2.2.8.4 or later
Downgrade to version 2.2.7 or earlier is prevented
SG250-10P, SG250-26HP/P,
SF250-48HP
manufactured with firmware 2.4.0.x
Downgrade from version 2.4 is prevented completely
SF250-24P, SG250-09HP, SG250-50HP, SG250-50P,
SG250X-24P,
SG250X-48P
manufactured with firmware 2.4.0.x
Can downgrade to version 2.3.5 (The first firmware version supported by these devices)
Sx350 series switches or Sx550 series switches with PoE manufactured with firmware 2.2.8.4 or later
Downgrade to version 2.2.7 or earlier is prevented
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