# EM7355 firmware interoperability and other questions **URL:** \ **Category:** General wireless topics\ **Created:** [January 13, 2015, 12:23pm UTC](https://forum.sierrawireless.com/t/em7355-firmware-interoperability-and-other-questions/7682 "2015-01-13T12:23:25Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![krzynier](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krzynier](https://forum.sierrawireless.com/u/krzynier)\ **Post date:** [January 13, 2015, 12:23pm UTC](https://forum.sierrawireless.com/t/em7355-firmware-interoperability-and-other-questions/7682/1 "2015-01-13T12:23:25Z")
Hello, will flashing firmware dedicated for other vendor rended the card unusable? Wll it change VID and PID? Is HP, Lenovo and Sierra-generic firmware switchable? I guess it may be not supported, but how does it work from technical point of view? Regards, Krzysztof ---
**Author:** ![Rex\_alex](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@Rex\_alex](https://forum.sierrawireless.com/u/Rex_alex)\ **Post date:** [January 14, 2015, 8:36am UTC](https://forum.sierrawireless.com/t/em7355-firmware-interoperability-and-other-questions/7682/2 "2015-01-14T08:36:38Z")
No…down loading different FW will not make the module get bricked(not usable) but however might have some registration/status issues depending on FW types. VID and PID will not be changed. I don’t think direct switching of FW is available but needs to be downloaded. thanks, Rex ---
**Author:** ![krzynier](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krzynier](https://forum.sierrawireless.com/u/krzynier)\ **Post date:** [January 19, 2015, 1:00pm UTC](https://forum.sierrawireless.com/t/em7355-firmware-interoperability-and-other-questions/7682/3 "2015-01-19T13:00:44Z")
Thanks, the answer was very helpful. Flashing generic firmware didn’t brick the modem and combination of cwe+nvu seems to work correctly. I have, however, problems running EM7355 under Linux. When first booting into Windows and rebooting into Linux, everything is ok. When cold booting into Linux - the modem refuses to go online: [size=85]OK AT+CFUN? +CFUN: 0 OK AT+CFUN=1 ERROR AT!PCINFO? State: LowPowerMode LPM force flags - W\_DISABLE:0, User:0, Temp:0, Volt:0, BIOS:1, GOBIIM:0 W\_DISABLE: 0 Poweroff mode: 0 LPM Persistent: 1[/size] Is there any possibility to force the modem go to Online mode or ignore the Bios LPM flag? rfkill doesn’t show any WWAN entry. mbimcli shows: Hardware Radio State: on Software Radio State: off I have also other problem: when modem is passed to Windows 7 Virtual Machine (regardless if host is on Windows or Linux), drivers for Modem, GPS, Network and Diagnostics couldn’t be started (This device cannot start - Code 10). Parent USB device doesn’t show any problems. The same OS image run on bare metal (VHD boot) works ok. Does the modem driver need to access some bare-metal hardware (possibly masked by virtualization layer) in order to work correctly? Regards, Krzysztof ---
**Author:** ![krzynier](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krzynier](https://forum.sierrawireless.com/u/krzynier)\ **Post date:** [January 21, 2015, 4:41pm UTC](https://forum.sierrawireless.com/t/em7355-firmware-interoperability-and-other-questions/7682/4 "2015-01-21T16:41:22Z")
I’ve observerd that enabling EM7355 USB interface number 8 (Network Device) under Windows changes the BIOS LPM flag. State: LowPowerMode LPM force flags - W\_DISABLE:0, User:0, Temp:0, Volt:0, BIOS:1, GOBIIM:0 W\_DISABLE: 0 Poweroff mode: 0 LPM Persistent: 0 OK State: LowPowerMode LPM force flags - W\_DISABLE:0, User:0, Temp:0, Volt:0, BIOS:0, GOBIIM:0 W\_DISABLE: 0 Poweroff mode: 0 LPM Persistent: 0 OK State: Online LPM force flags - W\_DISABLE:0, User:0, Temp:0, Volt:0, BIOS:0, GOBIIM:0 W\_DISABLE: 0 Poweroff mode: 0 LPM Persistent: 0 OK Which part in Linux drivers is responsible for this action? is this something related to usb\_clear\_halt()? I’ve also noticed some “magic” AT Command output sent to host: ^MODE: 5 What is source of this command? Regards, Krzysztof ---
**Author:** ![krzynier](https://avatars.discourse-cdn.com/v4/letter/k/b9bd4f/32.png) [@krzynier](https://forum.sierrawireless.com/u/krzynier)\ **Post date:** [January 29, 2015, 5:55pm UTC](https://forum.sierrawireless.com/t/em7355-firmware-interoperability-and-other-questions/7682/5 "2015-01-29T17:55:23Z")
Using QMI drivers S2.20N2.27 (and a workaround…) allowed to remove BIOS lpm force flag. Worked with CentOS 7 (kernel 3.10.0-123) Here are the steps: 1. Switch bConfigurationvalue to 1 2. Compile and load unmodified GobiUSBNet module 3. Unload this module 4. Load modified GobiUSBNet with added proper VID:PID (e.g. {QMI\_9X15\_DEVICE(0x03f0, 0x4e1d)}) (optional) 5. Load GobiSerial Module or qcserial (of course with proper VID:PID added) AT!PCINFO? shows modem in Online state after switching back to default configuration 2, mbimcli -d /dev/cdc-wdm0 --query-radio-state shows: Hardware Radio State: on Software Radio State: on Without loading unmodified module, the modified one hangs for about 15 second and probe fails with error -110. Regards, Krzysztof