FortiAP devices are thin wireless access points (AP) supporting the latest Wi-Fi technologies (multi-user MIMO 802.11ac Wave 1 and Wave 2, 4x4), as well as 802.11n, 802.11AX , and the demand for plug and play deployment.
Article Id 282012
Description This article describes how to recover U-series FortiAP from NVRAM corruption issues.
Scope FortiAP-U series.


U-series FortiAP continuing boot cycle.


Possible Reason:

This could be due to the following error in kp(kernel panic) output in FortiAP:


Line  681: <4>[206397.349823] Crashed FAP-OS: 7.0.0 build 31 release version.
Line  957: <4>[ 2269.884245] Crashed FAP-OS: 7.0.1 build 84 release version.


That means most crashes on 7.01-Build0084. 7.0.0-Build0031 was more stable on this FortiAP.


One option is downgrading the FortiAP to 0031 or flashing a .bin image on the FortiAP which is on Build84.


Flash image on FPA running Build84 if it is going through a continuous boot cycle:

  1. Get a .bin image from Fortinet support for the specific FortiAP model.
  2. Make the TFTP server ready for FortiAP.
  3. Console access ready for FortiAP.
  4. interrupted reboot loop, enter u-boot:Hit CTRL+c to abort u-boot in  3 secon 1 fap22b1!$.
  1. Under u-boot, perform below:

u-boot> dhcp

BOOTP broadcast 1

*** Unhandled DHCP Option in OFFER/ACK: 224

*** Unhandled DHCP Option in OFFER/ACK: 224

DHCP client bound to address


u-boot> setenv serverip               <<------------ tftp-server

u-boot> flash_ftnt_mft_img FAP_U231F-v7-build0084-FORTINET.bin

u-boot> reset



  • The above sample steps are applicable for U231F. It will be different if the FortiAP model is different.
  • The TFTP server is just an example here. Specify the IP address of the TFTP server running on the laptop or in the network.  Make sure this server is reachable from the FortiAP for the file transfer to work.
  • If FortiAP does not get an IP from the DHCP server, it is possible to assign a static IP.


To assign static ip address on the AP. Sample example below:



cfg  a AP_IPADDR=""

cfg -a AP_NETMASK=""

cfg  a IPGW=

cfg -c


  1. After step 5, the FortiAP will go through several boot cycles and it is necessary to wait for 3 -4 minutes. If a FortiAP login prompts are not getting, it is possible that the FortiAP might be booting with a non-FortiOS image. To force the FortiAP to boot with the FortiOS image, follow the steps below:


  • Stop at uboot on AP, when prompted:


Password: fap22b1!$

# set_image_id fap_default

# savenv

# reset


If the above point does not help, then Stop at uboot on FortiAP when prompted:


Password: fap22b1!$

# set_auto_learning off

# set_image_id meru_default

# savenv

# reset


Let the FortiAP boot with the Meru image.

On prompting for a password, use the Serial number as the password.

Use command <bootimg imageid 2> to boot with the FortiAP Image.