zukota.com Some little technical blog

Sierra Wireless EM7455: how to make it work with an older Lenovo laptop

6 min read zukota EM7455

Lenovo and other manufacturers, namely Dell are starting to use the newest Quallcomm 9×30 based cellular modems. The only modem manufacturer so far is Sierra Wireless and the model is XX7455, where XX is the form factor code. We’ll be using an m.2 modem, so our model number is EM7455. For the older generation laptops that only have a mini-PCI slot there’s the MC7455 model. Currently, the EM7455 is available as Sierra Wireless generic version (the model is EM7455), Lenovo version (the model is EM7455 as well), and Dell version (the model is DW5811e). All three versions are the same hardware, the only difference is the firmware and there are no restrictions for cross-flashing too.

EM7455 is not intended for use with the previous generation Lenovo laptops, such as X240, X1 Carbon Gen2, etc, but we’re going to fix that!

But if we check the price online we can see that the Dell variant is the cheapest, it can be bought for about $90, while Lenovo costing about $160. So I bought a Dell DW5811e from Aliexpress, the only thing to care about here is the part number, which should be 1102424. The part number is printed on the device sticker.

There are other part numbers around, one of which is known to be a 3G only model, so it’s not recommended to buy any other part number.

So when I got the module, there is the following to be realized:

  1. My laptop’s BIOS whitelist will accept only EM7345 and EM7355 modules. If any other device is installed, the laptop won’t boot with “1802 Unauthorized network card is installed” message. So in order to make it work, I need to change the ID to mimic the EM7355.
  2. I’m using Windows 7, and it lacks the generic MBIM driver, so the EM7455 won’t work out from the box. It will require the drivers, but the problem is, that the drivers from Sierra Wireless, Lenovo and Dell will work only for the device with the stock ID, and I cannot use those ID because of the #1. The solution here is to use the MBIM driver for the EM7355. If you’re using Windows 8 or 10, then you don’t need to worry about the MBIM drivers, as the Windows will use its built in drivers for that.

Put your laptop to sleep, open the case and install the EM7455. Secure the screw and connect the antennas properly. Then wake up the laptop. You’ll see the following unrecognized devices in the Device Manager:

In this case there are 4 devices total: MBIM interfaces, AT command port, NMEA GPS port and diagnostics port, the last 3 all being COM ports. If you see less than 4 devices, that can be because some of them disabled, refer to this post to enable missing COM ports and change the compostion to MBIM.

As for now, we cannot use the device as it is, because on next reboot we will see the 1802 error from BIOS. We need to change the IDs of the device to those whitelisted in our Lenovo BIOS. For the X240, we change the IDs to those mimicking EM7355.

Download and unpack the following file to the following path for example: “D:\DRV”

Open the properties window of the device that has the following ID: USB\VID_413C&PID_81B6&REV_0006&MI_03. Note the “MI_03” at the end, in case of a different ID, MI_03 always corresponds to the AT command COM port.

Then click “Update Driver”:

Click “Browse my computer for driver software”:

Select “Show All Devices” and click “Next”:

Click “Have Disk”:

Enter the path you extracted the drivers into: “D:\DRV\Driver\Driver\X64“. Use “D:\DRV\Driver\Driver\X86” if your Windows is 32 bit:

Click “OK”. You will see the following window. In the left list, select “Huawei Incorporated“, then in the right list, select “HUAWEI Mobile Broadband – Modem” and click “Next”:

You will see the following warning from Windows. Just click “Yes”:

The driver will be installed:

Click “Close” and check the device in the Device Manager:

Check the assigned COM port number in the “Modem” tab:

In our case, it is COM59. Now open that port COM59 in Putty or any terminal program. Type “ATI” and press Enter:

That means the device is working and we can change the device IDs now.

Enter the following commands and note the responses:

ate1
OK
at!entercnd="A710"
OK

Let’s check the current device VID/PIDs:

at!usbvid?
!USBVID:
413C
 
OK
at!usbpid?
!USBPID:
APP : 81B6
BOOT: 81B5
 
OK

Exactly the same IDs we see in the Device Manager. Let’s change the VID to Sierra Wireless:

at!usbvid=1199
OK

And PIDs to those mimicking EM7355:

at!usbpid=901F,9078
OK

Note that we set the boot ID to be 9078, that’s the standard ID for Lenovo PID. We need this PID to be Lenovo in order to be able to install drivers necessary when you need to flash your EM7455.

Let’s check if our changes are successful:

at!usbvid?
!USBVID:
1199
 
OK
at!usbpid?
!USBPID:
APP : 901F
BOOT: 9078
 
OK

All seems ok, let’s reboot the EM7455:

at!reset
OK

Your EM7455 will reboot and after a couple of minutes you’ll see it in the Device Manager. Note that device IDs will be changed now:

Download and unpack the following file (vanilla EM7355 drivers) into the following path: “D:\DRV\EM7355”

Now, if you have Windows 8 or later, the EM7455 MBIM device will be automatically recognized and drivers will be installed for it automatically. Proceed with the following step only if you have Windows 7.

Only for Windows 7: Open the device properties for “USB\VID_1199&PID_901F&REV_0006&MI_0c” and click “Update Driver”:

Click “Browse my computer for driver software”:

Navigate to “D:\DRV\EM7355\Uncompressed_Drivers_Only\Drivers” and click “Next”:

The driver will be installed:

Click “Close” and proceed with the following step no matter what Windows version you have.

Now for each of the remaining 3 devices without drivers repeat the above procedure, open the device properties, click “Update Driver” and point Windows to “D:\DRV\EM7355\Uncompressed_Drivers_Only\Drivers” if you have Windows 7 or 8, or to “D:\DRV\EM7355\Uncompressed_Win10Drivers_Only” if you have Windows 10:

You’ll end up with all device drivers correctly installed:

Now you can safely reboot your laptop without worrying about the 1802 error. Unfortunately, with my X240 I see the following message every time I reboot the laptop:

For some odd reason, the X240 BIOS recognizes the EM7455 as an SSD disk. This can potentially be fixed by isolating some m.2 contacts on the EM7455 that are used for SSD signals by the X240 motherboard, but I didn’t investigate that. I press ESC every time I reboot to skip that error. I reboot rarely and use sleep all the time, anyways. With the newer Lenovo laptops, you won’t see this error as their motherboard is already aware of the EM7455.

Congratulations, your EM7455 is ready to use with your older Lenovo laptop!