Technical Tip: How to fix 'Failed: upgrade script not found' error when upgrading APs managed by FortiWLC controller

[harshithbn]

Description	This article explains the steps to fix the upgrade failure seen with Access Points managed by legacy Forti-WLC controller.
Scope	FortiWLC-8.5.x firmware and above.
Solution	The Access Points managed by the Forti-WLC controller must run the same firmware version as controller to serve clients. If there's a mismatch, APs will transition from 'Enabled Online' to 'Disabled Online' and get stuck at 'Downloading configuration data', eventually entering a reboot loop. In such cases, a forced upgrade on AP to match the controller's firmware is required. If the AP displays the error 'Failed: upgrade script not found' during this process, it likely indicates that the firmware file has been deleted from the controller’s cache. Example:  controller(15)# upgrade ap same 823 force  remote This will overwrite all existing system images. Are you sure [y|n]? y Current Version is 8.5-5build-3 sh: /opt/meru/images/forti-8.6-7build-2/is_downgrade.pl: No such file or directory 823 AP-823           |                         | Failed: upgrade script not found While in this state, verify the current controller firmware by running the 'show controller' command, and then confirm if the same firmware is listed as the Running Image using the command below:   controller(15)# show images  Running image : image0 On reboot     : image0 -------------------------------------------------------------------------------- Running image details. System version: 0.6.6 System memory: 1659M/2022M Apps version: 8.6-7build-2 Apps size: 2931M/3644M -------------------------------------------------------------------------------- Other image details. System version: 0.6.6 System memory: 1674M/2031M Apps version: 8.5-5build-3  Apps size: 2949M/3643M  If the flash images match, check whether the corresponding file folder exists in the images directory, as shown below:    controller(15)# dir total 2528 -rw-r--r-- 1 root root  27666 Feb 25 21:57 backupnew.txt -rwxr-xr-x 1 root root 124214 Jun 28 04:32 config-factory.tgz -rw-rw-rw- 1 root root 703762 Jan  4  2023 configuration -rw-r--r-- 1 root root 748006 Jun 23  2022 files.tgz drwxrwxrwx 5 root root   4096 Jun 28 04:32 forti-8.6-7build-2        <====== lrwxrwxrwx 1 root root     76 May  7 16:04 forti-controller-diagnostics.fortiwlc42.2025-05-07.16-04-08.tar.xz -> /ssd/diag/forti-controller-diagnostics.fortiwlc42.2025-05-07.16-04-08.tar.xz lrwxrwxrwx 1 root root     18 Dec  4  2021 lastdiag -> /ssd/diag/lastdiag lrwxrwxrwx 1 root root     35 Jun 28 04:32 mibs.tar.gz -> forti-8.6-7build-2/mibs/mibs.tar.gz -rw-r--r-- 1 root root  32844 Jun 28 04:31 pre-upgrade-config -rw-r--r-- 1 root root 703730 Jan  4  2023 run lrwxrwxrwx 1 root root     20 Aug  5  2022 s_lastdiag -> /ssd/diag/s_lastdiag -rw------- 1 root root  34561 Jun 30 19:21 script.log -rw-r--r-- 1 root root  32161 Jun 27 15:26 startup-config -rw------- 1 root root 154812 Apr 12  2022 startup-config.np1 -rw-rw-rw- 1 root root   1043 Jun 27 19:01 upgrade.log If the folder 'drwxrwxrwx 5 root root 4096 Jun 28 04:32 forti-8.6-7build-2' is missing, Access Points will fail to download the current firmware. As a result, any newly connected APs will remain in the 'Disabled Online' state due to the inability to retrieve the required firmware. Solution:  The missing folder can only be restored by reapplying the same firmware upgrade to the controller. After the controller upgrade, verify that the folder is present. Once confirmed, perform a forced upgrade of the Access Point to match the controller firmware. controller(15)# upgrade ap same 823 force remote   The steps an Access Point follows to complete a successful upgrade are outlined below. Upgrading APs | Upgrade Requested   Upgrading APs | Erasing Flash  Upgrading APs | Erasing Flash Done Upgrading APs | Writing Flash Upgrading APs | Verifying Write  Upgrading APs | Reboot Requested  Upgrading APs | Success: Rebooted  The AP status post successful upgrade will look like below:  Controller(15)# show ap 823 Access Points AP ID                      : 823 AP Name                    : AP-823 MAC Address                : 00:0c:e6:22:03:aa Uptime                     : 00d:00h:00m:09s Location                   :  Building                   :  Floor                      :  Contact                    :  Operational State          : Enabled Availability Status        : Online Path MTU State             : autodiscovered Path MTU                   : 1500 Jumbo MTU State            : disable Jumbo MTU                  : 1500 Alarm State                : No Alarm LED Mode                   : Normal AP Init Script             : l3_script.scr Boot Image Version         : 1.0 FPGA Version               :  Runtime Image Version      : 8.6-7build-2 Connectivity Layer         : None Dataplane Encryption       : None Parent MAC Address         : 00:00:00:00:00:00 Parent AP ID               : 0 Link Probing Duration      : 120 AP IP Address for L3       : 0.0.0.0 AP Model                   : AP822e Latitude Longitude         :  Zip Code                   :  Area Code                  : 0 City Name                  :  State Name                 :  Timezone                   :  Hardware Revision          :  Power Supply Type          : 802.3-at AP Indoor/Outdoor type     : Indoor KeepAlive Timeout(seconds) : 60 VLAN Name                  :  AP Hardware Serial Number  : 123123 Ap Group Id                : 0 Feature Group Id           : 0 Operating Mode             : Normal Dual 5GHz Radio Mode       : off Related article:  Meru Technical Note - How to upgrade AP m... - Fortinet Community