Problems with Sierra Wireless EM7305

Harald Jung harald.jung at
Wed Jul 13 10:07:42 UTC 2016


it's an internal modem. I'll try it with a different notebook later.
Have you tested other modems with the product_id 9041?
Seems to be a newer version, only to be shure that the 9041 was already 
Brother google didn't helped me with this id yet.


On 13.07.2016 10:20, Bjørn Mork wrote:
> Harald Jung - ECOS Technology <Harald.Jung at> writes:
>> when I try to run the modem with qmi support, nm-applet askes for the
>> pin.  The SIM accepts the PIN and after a while the motdem resets
>> itself and disappears from the usb bus, to show up after 1-2 seconds
>> again.
> This is a modem firmware reset/crash which we really cannot influence.
> Except: I struggled with something similar recently.  In my case the
> modem would work as long as I limited the modem to 3G.  But it would
> reset ss soon as it registered in an LTE network.
> This turned out to be a simple voltage drop problem.  I used a bad USB
> extension cable between the host and the modem, and I guess the voltage
> dropped below the brownout reset protection when there was a current
> spike .
> Don't know it your problem is the same.  But it could certainly be from
> the description.  There will be a current spike righth after entering
> the PIN since the modem then will enable the radio and start searching
> for networks.  So the first you should do is to check cables, connectors
> and power supplies. If this is a laptop internal modem, then I guess
> your only real option is to try to reseat it.  Possibly after cleaning
> the contacts carefully,
> Or simply move the modem to another host and see if that helps.  If it
> does, then there is a problem wtih the host/socket.  If it doesn't help,
> then there might be a modem hardware problem.
>> If I do it to often, the Modem changes its product_id to 9040 and has
>> only 1 Interface (udev loads qcserial) and only 1 bConfiguration
>> Value.
> That's the modem bootloader.  Likely an intentional failsafe kicing in
> because of the repeated resets.
>> And it doesn't work at all, the only thing which helps is to remove all power supply.
> The single serial port speaks one or more of a number of obscure
> Qualcomm protocols.  It's used for ramdumps, flash upgrades and probably
> more.  But ModemManager does not support any of these protocols.
>> After that it shows up with the product_id 9041 again.
>> Kernel Version is 4.5.7
>> When I Try to run the modem in mbim mode, I'll get this messages:
> The MBIM failure seems unrelated. It never reaches the point where the
> modem searches for networks, so you avoid the reset.
> Bjørn

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