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T470 No GPS COM port for WWAN

T430-T490, T530-T590 Series
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Jake.Werecat
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T470 No GPS COM port for WWAN

#1 Post by Jake.Werecat » Thu Apr 21, 2022 5:58 pm

I recently upgraded my hardware from T430 to T470. It's a great machine, however I'm having a little trouble with installing WWAN card on Win10. The latest drivers from Lenovo website are installed, cellular network appears in Notifications, card is visable in Device Manager, but there are no COM ports assosiated. Neither for modem AT commands (not very important for me), nor for GPS NMEA output (top important for me). No errors or missing drivers in Device Manager.
Modem is a Lenovo-branded Sierra EM7455.
Anybody ever run into similar issue?
T470

Jake.Werecat
Junior Member
Junior Member
Posts: 273
Joined: Thu May 09, 2019 6:46 pm
Location: Europe

Re: T470 No GPS COM port for WWAN

#2 Post by Jake.Werecat » Fri Apr 22, 2022 10:32 pm

All right, it seems that I am the best at solving my own problems. I fixed the issue, however it's a bit complex....and crazy stupid. OK, let me elaborate.
There are two different modem install configurations possible; first one installs two COM ports, one for modem AT Commands and one for GPS/NMEA string out, second configuration does not install any of those.
By default up to win7 we have those COM ports, from win 8 onward we don't. Why? No idea.
Now what's important is that in older drivers it was possible to override those defaults and install the full mode, in later versions this functionality was removed, I don't know why, neither I know if it was Lenovo or Sierra decision.
But, as almost always fortunately there is a workaround.
1)First it's good to update the firmware manually, as we will be using old driver. Use this link: https://source.sierrawireless.com/-/med ... 2_001.ashx
2)Then we download old driver for P50/P70
https://support.lenovo.com/id/pl/downloads/ds112781
3)And choose to extract only (without installing).It will be extracted to default location.
4)We go to C:\DRIVERS\WIN\WWAN\Configuration.ini and do some modifications:
-USBCOMP=8
-LOCATIONDRIVER=0
-WIN8LOCATION=0
-FWUPDATE=OFF
(USBCOMP should be enough, but it appears that it's not, so I advice to flip both LOCATION parameter to 0 as well, as it forces the installer to install COM ports, we set FWUPDATE flag to OFF to prevent the installer from downgrading our manually upgraded firmware)
5)Next we install the driver normally, by running setup.exe.
6)Voila! Long awaited COM ports appear
Image

It seems that there ain't no up to date guides for this issue, so I believe it might be worth preserving for others.
On the other hand - It does work, however I just cannot find my words for how STUPID this issue is. It's not a bug, it's a deliberate decision by either Lenovo or Sierra (or both).... I'm wondering if the situation with Fibocom L831 which is another whitelisted WWAN for T470 is any better...
T470

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