Are you uploading the Fortiap Firmware on the Fortigate via GUI and upgrading together all at a time.
You can upgrade the firmware few AP at a time instead of all together with the specifying the serial number on the below command
- Upload the FortiAP image to the FortiGate unit.
For example, the Firmware file is FAP_22A_v4.3.0_b0212_fortinet.out and the server IP address is 192.168.0.100.
execute wireless-controller upload-wtp-image tftp FAP_22A_v4.3.0_b0212_fortinet.out 192.168.0.100
If your server is FTP, change
ftp, and if necessary add your user name and password at the end of the command.
- Verify that the image is uploaded:
execute wireless-controller list-wtp-image
- Upgrade the FortiAP units:
exec wireless-controller reset-wtp all
If you want to upgrade only one FortiAP unit, enter its serial number instead of
Kindly refer the below document .