The Sierra MC7355 can run configurations for several North American carriers. These cards are easy to find on eBay and notable for their support for the Sprint LTE network. Unless you're luck out, you may find you need to flash a new carrier configuration onto the card you purchased before using it.
These procedures are specific to the setup I had to perform this on. Most notably, the only system I had with a mini-PCI-e slot was the target pfSense system, a PCengines APU1d with no VGA port (serial console only). If you're able to obtain a USB-to-mini-PCI-e adapter, performing this flash will likely be much easier (perhaps even allowing you to use Windows in a VM).
System: PCengines APU1d Live USB: FreeBSD (i386 memstick installer) Live USB: Arch linux Modem: Sierra MC7355, with Panasonic SKU (1101888) Also used: Null modem adapter with USB-to-serial plugged into a spare machine Two USB sticks
For this step, we need to access the modem's USB Serial interface. This will allow us to use modem AT Commands to inspect the current configuration and turn off MBIM mode which prevents the modem from being discovered in Linux. Since Linux wont (AFAICT) recognize the modem in this state, we need to rely on FreeBSD's u3g driver.
Write the FreeBSD installer image to a spare USB stick and boot. Serial console should work out of box (speed: 115200). Go with the default multi-user boot and select the LiveCD option.
First, verify your modem was found:
# dmesg | less
Look for something like this:
u3g0: <vendor 0x1199 MC7355, class 0/0, rev 2.00/0.06, addr 3> on usbus1
u3g0: Found 4 ports.
The driver will create four USB-serial ports
# ls /dev/cuaU*[0-9]
/dev/cuaU0.0 /dev/cuaU0.1 /dev/cuaU0.2 /dev/cuaU0.3
The port for AT commands is usually on cuaU0.1 or cuaU0.2. Try an AT command with each, pressing ~. to exit
the session
# cu -l /dev/cuaU0.1
Connected
AT
OK
Note: if you see the OK but AT isn't echoed to your screen, enter ATE to turn echo on
Some of the AT commands we need require us to be in password-protected mode. The default password for these modems is A710
AT!ENTERCND="A710"
OK
Before proceeding, we need to check the current carrier to see whether we really need to do a flash
AT!GOBIIMPREF?
!GOBIIMPREF:
preferred fw version: 01.08.16.05
preferred carrier name: VZW
preferred config name: VZW_000.036_000
current fw version: 01.08.16.05
current carrier name: VZW
current config name: VZW_000.036_000
OK
In this case, I want Sprint. Let's see if a Sprint config is loaded that we can choose:
AT!PRIID?
PRI Part Number: 9902812
Revision: 01.07
Carrier PRI: 9999999_9902266_SWI9X15C_01.08.16.05_00_VZW_000.036_000
If our preferred carrier appeared here, we could switch to it with this command (note how the string above maps to the three fields):
AT!GOBIIMPREF="01.08.16.05","VZW","VZW_000.036_000"
Since it doesn't map, we'll need to continue
We need to ensure no MBIM interface is enabled for Linux to see our modem correctly. First, check the current setting:
AT!UDUSBCOMP?
!UDUSBCOMP: 14
OK
List the settings to see what this maps to:
AT!UDUSBCOMP=?
0 - reserved NOT SUPPORTED
1 - DM AT SUPPORTED
2 - reserved NOT SUPPORTED
3 - reserved NOT SUPPORTED
4 - reserved NOT SUPPORTED
5 - reserved NOT SUPPORTED
6 - DM NMEA AT QMI SUPPORTED
7 - DM NMEA AT RMNET1 RMNET2 RMNET3 SUPPORTED
8 - DM NMEA AT MBIM SUPPORTED
9 - MBIM SUPPORTED
10 - NMEA MBIM SUPPORTED
11 - DM MBIM SUPPORTED
12 - DM NMEA MBIM SUPPORTED
13 - Config1: comp6 Config2: comp8 NOT SUPPORTED
14 - Config1: comp6 Config2: comp9 SUPPORTED
15 - Config1: comp6 Config2: comp10 NOT SUPPORTED
16 - Config1: comp6 Config2: comp11 NOT SUPPORTED
17 - Config1: comp6 Config2: comp12 NOT SUPPORTED
18 - Config1: comp7 Config2: comp8 NOT SUPPORTED
19 - Config1: comp7 Config2: comp9 SUPPORTED
20 - Config1: comp7 Config2: comp10 NOT SUPPORTED
21 - Config1: comp7 Config2: comp11 NOT SUPPORTED
22 - Config1: comp7 Config2: comp12 NOT SUPPORTED
OK
In the case above, 14 maps to configs 6 and 9. To do the flash in Linux, we need the AT and QMI interfaces which is 6 but we dont want the MBIM interface in 9.
Caution: ensure you do not set this to an interface without AT - this may lock you out of the modem
Set the USB interface to config number 6:
AT!UDUSBCOMP=6
OK
From here, we should be good to start with the Linux half
To complete this we need a live linux environment with a serial console. For this I used an Arch installer. If using Arch, a second USB or system drive will be necessary as the live install's root partition is not big enough for the compile dependencies. If another live distro is chosen, the requirements are:
- Boots with a serial console (minimum: grub configured on serial console)
- Ability to compile kernel modules (basic compiler tools, linux headers)
Arch's Grub uses port speed 38400 so switch your terminal emulator accordingly
To boot into the live environment, at the Grub boot prompt press TAB and append console=ttyS0,38400 to the kernel commandline as described in the Arch wiki articleWorking with the serial console. Log in as root
We need more space, so plug your 2nd drive in now. In this example, our second drive is /dev/sdc
First, verify you're working with the drive you think you are
# dmesg | tail # Look for the messages for the drive just plugged in
# fdisk -l /dev/sdc # Verify the disk size matches expectations
From here we'll be following the Arch Installation Guide up to the Chroot section
- Create a new primary partition if one doesn't already exist using
fdisk /dev/sdc - Format it:
mkfs.ext4 /dev/sdc1 - Mount it:
mount /dev/sdc1 /mnt - Install base packages:
pacstrap /mnt base base-devel linux-headers - Switch into the new root:
arch-chroot /mnt
Optionally, you can continue along the installation to make this new USB a persistent bootable system you can use in the future
The Sierra modem may be identified by several built-in kernel drivers that are incompatible with the drivers we're about to compile. Remove any of the following modules with modprobe -r <modulename>:
- qcserial
- qmi_wwan
- usb_wwan
- cdc_mbim
- cdc_wdm
- cdc_ncm
- sierra
- sierra_net
The software provided by Sierra for flashing this modem requires the Qualcomm Gobi drivers. Sierra calls these the Linux Drivers QMI Software
First, download and unpack the drivers:
# pacman -S wget unzip # these arent installed by default
# cd /usr/src
src] # wget http://www.downloads.netgear.com/files/aircard/Linux-Support-S2.13N2.25.zip
src] # unzip Linux-Support-S2.13N2.25.zip
src] # mv -v Linux-Support-S2.13N2.25/Linux\ Drivers\ S2.13N2.25/GobiSerial .
src] # mv -v Linux-Support-S2.13N2.25/Linux\ Drivers\ S2.13N2.25/GobiNet .
Next, if you're using a 4.x series Linux kernel you may need this patch to get it to compile
src] # curl https://gist.githubusercontent.com/mleinart/373971d3560fa5814a684de2d9068eba/raw/1bc83506bb9c38d995b8fdcfe1e555c5f4a89528/Sierra-QMIDrivers-fix_compile_errors.diff | patch -p0
Finally, compile and install each driver:
src] # cd GobiSerial
GobiSerial] # make install
GobiSerial] # modprobe GobiSerial
GobiSerial] # cd ..
src] # cd GobiNet
GobiNet] # make install
GobiNet] # modprobe GobiNet
And now verify they found your modem
# dmesg | tail
# ls /dev/qcqmi0
/dev/qcqmi0
# ls /dev/ttyUSB*
/dev/ttyUSB0
/dev/ttyUSB1
/dev/ttyUSB2
Note: Sometimes this modem is finicky in linux - I've had some luck removing the module and re-inserting while the system is running
Firmwares for the MC73XX series are located at the (source.sierrawireless.com site)[http://source.sierrawireless.com/resources/airprime/software/airprime-mc73xx-fw-package-build-4544/] You'll want the SPK version of the package which includes carrier-approved firmware as well as the carrier configs bundled in individual files.
The firmware flashing tool is part of the (Linux QMI SDK Software package)[http://source.sierrawireless.com/resources/airprime/software/linux-qmi-sdk-software-04,-d-,00,-d-,00/] provided by Sierra.
First, extract the Firmwares someplace
# mkdir /usr/src/sierra_firmware
# unzip -d /usr/src/sierra_firmware Build4544-Approved-7355-SPK.zip
Copy the full pathname of the SPK file for the carrier you want. You'll need to paste it in later Now, compile the Image loader tool for the MC7xxx series:
# mkdir SLQ
# cd SLQ
SLQ] # tar zxvf ../SLQS04.00.00.bin.tar.gz
SLQ] # cd SampleApps/MC7xxx_Image_Management
MC7xxx_Image_Management] # make
Finally, execute the tool. If the tool is missing options 1-4, it means the QMI drivers aren't active. Check for /dev/qcqmi0 and see the driver section above.
# ./bin/mc7xxximgmgmthosti686 -s ../../build/bin/hosti686/slqssdk
Running with device in application mode
Please select one of the following options or press <Enter> to exit:
1. Display the information for the executing device image
2. Download a boot loader image to the device
3. Download a firmware image to the device
4. Download an NV item to the device
5. Display the information for a particular spk/cwe image located on the host
6. Display the information for a particular nvu image located on the host
7. Image Switching on MC/EM74xx
8. Get valid fw/pri combination for MC/EM74xx
Option:
Select option 3 and paste the full path to the SPK file Allow the firmware download to complete and your modem should now be active!
# pacman -S uucp
# cu -l /dev/ttyUSB2 # or ttyUSB1, varies
Connected.
AT
OK
AT!ENTERCND="A710"
OK
AT!GOBIIMPREF?
!GOBIIMPREF:
preferred fw version: 05.05.63.01
preferred carrier name: SPRINT
preferred config name: SPRINT_005.037_000
current fw version: 05.05.63.01
current carrier name: SPRINT
current config name: SPRINT_005.037_000
OK
Success!
Here are some pasted errors to help Googlers to reach this page
See this gist for a patch: https://gist.github.com/mleinart/373971d3560fa5814a684de2d9068eba
/usr/src/S2.26N2.38/GobiSerial/GobiSerial.c:325:14: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
.resume = usb_serial_generic_resume,
^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/src/S2.26N2.38/GobiSerial/GobiSerial.c:325:14: note: (near initialization for ‘GobiDriver.resume’)
/usr/src/S2.26N2.38/GobiSerial/GobiSerial.c:326:20: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
.reset_resume = usb_serial_generic_resume,
^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/src/S2.26N2.38/GobiSerial/GobiSerial.c:326:20: note: (near initialization for ‘GobiDriver.reset_resume’)
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:296: /usr/src/S2.26N2.38/GobiSerial/GobiSerial.o] Error 1
make[1]: *** [Makefile:1471: _module_/usr/src/S2.26N2.38/GobiSerial] Error 2
make[1]: Leaving directory '/usr/lib/modules/4.8.6-1-ARCH/build'
make: *** [Makefile:16: all] Error 2
See this gist for a patch: https://gist.github.com/mleinart/373971d3560fa5814a684de2d9068eba
/usr/src/S2.26N2.38/GobiNet/GobiUSBNet.c: In function ‘GobiUSBNetStartXmit’:
/usr/src/S2.26N2.38/GobiNet/GobiUSBNet.c:1329:8: error: ‘struct net_device’ has no member named ‘trans_start’; did you mean mem_start’?
pNet->trans_start = jiffies;
^~
make[2]: *** [scripts/Makefile.build:290: /usr/src/S2.26N2.38/GobiNet/GobiUSBNet.o] Error 1
make[1]: *** [Makefile:1471: _module_/usr/src/S2.26N2.38/GobiNet] Error 2
make[1]: Leaving directory '/usr/lib/modules/4.8.6-1-ARCH/build'
make: *** [Makefile:37: all] Error 2
Having an MBIM config (or maybe it's just any multi-config UDUSBCOMP value?) makes Linux USB angry, causing the modem's Serial devices to not work
[ 484.038683] usb 3-1.3: config 1 has an invalid interface number: 8 but max is 3
[ 484.038693] usb 3-1.3: config 1 has no interface number 1
[ 484.039172] usb 3-1.3: config 2 has an invalid interface number: 12 but max is 1
[ 484.039181] usb 3-1.3: config 2 has an invalid interface number: 13 but max is 1
[ 484.039189] usb 3-1.3: config 2 has an invalid interface number: 13 but max is 1
[ 484.039196] usb 3-1.3: config 2 has no interface number 0
[ 484.039203] usb 3-1.3: config 2 has no interface number 1
I believe this guide is obsoleted by
libqmipackage in Arch Linux which includesqmicliandqmi-firmware-updateprograms that allow you to flash any modem with QMI interface without using proprietary SDKs.