The firmware image became corrupted when there was an attempt to upgrade the firmware from the GUI.
These error messages during the firmware upgrade process display:
Cannot read the file on access point
The software upgrade was interrupted and was not able to be completed
File not found, server not found or invalid file format
You can use the MODE button when the access point has a corrupt firmware image. On 350 series access points, you cannot use the MODE button to reload the image file, but you can use the CLI through a Telnet or console port connection. Complete these steps in order to proceed with the Mode Button Procedure.
These are the steps for Cisco IOS reload with the MODE button:
The PC that is intended to use must be configured with a static IP address in the range of 10.0.0.2 to 10.0.0.30.
Make sure that the PC contains the access point (AP) image file in the Trivial File Transfer Protocol (TFTP) server folder and that the TFTP server is activated.
Rename the access point image file in the TFTP server folder to c1200-k9w7-tar.default.
Use a Category 5 (CAT5) Ethernet cable in order to connect the PC to the access point.
Disconnect power / hold the MODE button / reconnect power / wait 20 sec until LED light turns red and release MODE button.
After the reboot, the AP begins to load the Cisco IOS image from the TFTP server.
If this does not work, then complete this workaround solution:
Note: Make sure that the computer and the AP are in the same subnet, for example and AP in default settings has IP: 10.0.0.1, so you need to have the computer as IP 10.0.0.2, subnet mask: 255.255.255.0 and default gateway: 0.0.0.1.
Open the TFTP server and make sure that the TAR file name is shown as in the web site, because it can be renamed to Download.tar, and if that happens, it needs to be renamed. Choose TAR file and then choose Ok.
Telnet the unit, go to enable mode and enter this command: