This is why static IP addressing is not recommended <smile>Best to always use DHCP.  To recover your AP without console you will have to configure a DHCP server to provide an IP address to the AP.  Without an IP address the AP won't be able to do any...

Cable length is a function of the ETHERNET and POE standards not the AP specifications! Refer to the relevant IEEE 802.3 standards documents for those cable length specifications. Remember longer cable = greater power loss for POE.

Agreed - do not try to combine upgrade and addressing change. You'll need to break HA to make the addressing changes (break HA, change IPs, re-establish HA) so keep that separate and upgrade the OS while HA is working normally with both units up.

Review these guides:https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/220443-how-to-avoid-boot-loop-due-to-corrupted.htmlhttps://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/...