FGR-70F-3G4G WWAN interface drops when pushing firmware from Fortimanager

[sgale]

We are encountering an issue with upgrading our firewalls over cellular. 

During the firmware update the firewalls wwan connection drops and the firmware push fails. (hangs at 36%)

Could this be related to the Modem firmware or is there a setting that needs to be updated to prevent this from happening?

Are there any diagnostics to troubleshoot this issue?

FGR-70F-3G4G 7.2.6b1575 -->7.4.7b2731

LTE Modem EM7565 Firmware SWI9X50C_01.08.04.00 (Generic)

Fortimanager 7.6.4 b3579

[Anthony_E]

Hello,

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible.

Thanks,

Anthony

[Anthony_E]

Hello,

We are still looking for someone to help you.

We will come back to you ASAP.

Thanks,

[Anthony_E]

Hello,

Did you already open a TAC ticket with the support: https://support.fortinet.com/welcome/#/

Regards,

Anthony

[sgale]

We've also found that the LTE modem disconnects when a host PC on the network is downloading patches or when we try to push a fortiswitch upgrade over the cell link. 

I have an outstanding ticket with TAC as well. 

[sgale]

Update:

The issue seems to be related to the cellular link being saturated during a firmware push or when a client is downloading a patch. 

Event Logs show 

LTE modem IPV4 data link changed from 
QMI_WDS_CONNECTION_STATUS_CONNECTED to QMI_WDS_CONNECTION_STATUS_DISCONNECTED

This kills any connections. The cell interface comes back up approximately 5-6 seconds later. 

Is there some sort of keepalive that could be failing causing the cell modem to reset itself?