Mc7455, FOTA and USB2

Hi,

I have a mc7455 connected to a mikrotik board which doesn’t support usb 3.0 and therefor I use the at!usbspeed=0 command to set it as usb 2.0 only.

If I don’t do this it won’t be recognized by the router.

I tried moving to Verizon FW on the device that didn’t support this command and had to tapeout the pins in order to upgrade the FW but then I had to reapply the command to enable usb2.

My question is, if I had done a FOTA upgrade to the old Verizon FW instead of moving to it would it keep the usb2 setting?

Just to clarify the order of actions I want to do:

  1. Have a device running latest generic and usb2 mode set by at command
  2. Preform FOTA upgrade of old Verizon FW(upgrade to same version as generic) , causing a switch to Verizon FW and restart
  3. Now would I get the device running latest Verizon FW and usb2?

Hi uriel,

Please try to upgrade to the latest SWI9X30C_02.33.03.00_00_VERIZON firmware and try again. I can set at! usbspeed=0 on firmware SWI9X30C_02.33.03.00_00_VERIZON.
You can get it here AirPrime EM/MC74xx Approved FW Packages

Help to tick “Solutions” if your question is answered.

Hi Donald,

I know that the latest Verizon FW supports the usbspeed AT command that is not the problem.

The problem is what happens when you do an FW upgrade, does the at!usbspeed=0 persists?

Hi uriel,

I try on my MC7455 module. The at!usbspeed=0 is not persistent when switching to Verizon firmware. It also is not persistent when performing the FOTA upgrade of Verizon firmware.

That’s not good, it means that anyone using the at!usbspeed command are unable to switch FW or upgrade…

Is there a way to inject a startup script to the modem?

@uriel

No you cannot have a script running on the unit.

Regards

Matt

So what is the solution for someone who needs to use at!usbspeed=0 in order to be it recognized in his router?

Can you set the FW to have the default at!usbspeed=0? any other fix?

@uriel

According to my testing if you set the NV item which sets the speed then it does hold the value as per the below.

at!entercnd="A710"
OK
at!usbspeed?
SUPPORTED:Super-Speed
CURRENT  :High-Speed

OK
at!usbspeed=0
OK
at!reset    //Reset for the change to take effect
OK
at
OK
ati
Manufacturer: Sierra Wireless, Incorporated
Model: MC7455
Revision: SWI9X30C_02.36.00.00 r8395 CARMD-EV-FRMWR2 2020/10/28 06:33:51
MEID: 35907206005151
IMEI: 359072060051519
IMEI SV: 22
FSN: LQ545100810110
+GCAP: +CGSM


OK
at!entercnd="A710"
OK
at!usbspeed?
SUPPORTED:High-Speed
CURRENT  :High-Speed

OK
at       //Downgraded firmware here
OK
ati
Manufacturer: Sierra Wireless, Incorporated
Model: MC7455
Revision: SWI9X30C_02.33.03.00 r8209 CARMD-EV-FRMWR2 2019/08/28 20:59:30
MEID: 35907206005151
IMEI: 359072060051519
IMEI SV: 20
FSN: LQ545100810110
+GCAP: +CGSM


OK
at!entercnd="A710"
OK
at!usbspeed?
SUPPORTED:High-Speed
CURRENT  :High-Speed       //Setting has been maintained

OK

What I haven’t done is test it with a firmware where the command does not exist to check the NV item but I can’t see a reason if you set the speed with a firmware version that can set it, why it would be reset if you downgraded, you just would not be able to set it to anything else unless you upgraded it. Clear?

Regards

Matt

@mlw if that is the case then it should be OK, just needs to be careful not to move to any FW that doesn’t support it.

How did you downgrade the FW? did you use AirVantage FOTA? due to the fact that I don’t have an FW update tool in my router that is all I can use.

@uriel

I used a one click updater over USB but the principle is the same.

Regards

Matt

@mlw I confirm this works! had a device with at!usbspeed=0 running latest generic, upgraded to latest verizon and it didn’t break :slight_smile: