Sierra Wireless EM7455

[Bjørn Mork]

Dan Williams <dcbw at redhat.com> writes:
> On Thu, 2016-06-09 at 18:03 +0200, Ralph Plawetzki wrote:
>
>> I see. I am not sure whether it says 'Lenovo' or 'Sierra' on lsusb.
>
> Sierra's vendor id is 1199.  If your device (as reported by lsusb) is
> not 1199, then it's a OEM-ized device and probably subject to the BIOS
> lock that I explained in the previous mail.

No, I believe Dell, HP, Toshiba, and probably others, do this.  But
Lenovo doesn't. They use the Sierra vendor ID.  The Lenovo modems from
Sierra are labelled and identified as Sierra modems, with an additional
Lenovo part number.  So the Lenovo BIOS whitelist includes specific
Sierra VID:PID combos.  It's been like that with other modem brands,
too, like the Ericsson modems in the past.

But the PID is customized. At least on the EM7455. I believe the 9078
(boot) and 9079 (appl) PIDs are specific for the Lenovo version. The
"normal" EM7455 use the same PIDs as the "normal" MC7455 (i.e. 9070 and
9071).  Lenovo also use a customized iProduct string descriptor for some
reason.  The default is simply "EM7455", while Lenovo use "Sierra
Wireless EM7455 Qualcomm Snapdragon X7 LTE-A".  It's a bit weird that
they don't include "Lenovo" there, but I assume all this is ruled by
money, and that Qualcomm pays their share for the Snapdragon
commercial...

For the curious: The PIDs and iProduct string are customized via the
USB_APP_BOOT_PIDS and USB_PROD_NAME NVRAM variables.




Bjørn