Bus communication error: -84

I have install the driver and get this error how can I fix it??
[ 101.946231] sdhci: ===========================================
[ 101.946282] wfx-sdio mmc0:0001:1: write32: bus communication error: -84
[ 101.954796] wfx-sdio mmc0:0001:1: bus returned an error during first write access. Host configuration error?
[ 101.963722] >>>>> err2 wfx_init_device(wdev)
[ 101.963733] >>>>> err2 wfx_probe<4>[ 101.964001] wfx-sdio: probe of mmc0:0001:1 failed with error -5

error is at line: 337
main.c (13.5 KB)

Hi T_a,

What device and current firmware are you using? Do you follow instruction from Sierra source page?


I have use WP7605 Module and the pic below is fw that I have used.

Hi T_a,

To install driver on Linux, please download and extract the package named “MBPL_Drivers_R24_ENG3-src.tar” from the link below.


Choose PCIe or USB, then follow readme.txt step-by-step to install the driver.


hello, jerdung

Does this driver is for ubuntu?
I have install to my ubuntu then my /ttyUSB0-2 is lost how can I get it back??

Hi T_A

Yes, this driver is for ubuntu. AT port interface should be exposed as /dev/ttyUSB0 or dev/ttyUSB2. Could you try to reconnect your module to the host?


I have reconnect my module and it still cannot find /dev/ttyUSB0 to /dev/ttyUSB2
Are you sure that it can use with wp7605 module?
before I install the driver , I can still see USB0.

However, how can i fix “wfx-sdio mmc0:0001:1: write32: bus communication error: -84” ??

Hi T_a,

MBPL is the official driver for all WP76xx products. It’s strange that your AT interface is not shown as ttyUSB0 or ttyUSB2. I’m trying to investigate that.

Where did you get the driver before? I’m not sure the driver that isn’t on Sierra source page could work properly.

I have install this ( GitHub - SiliconLabs/wfx-linux-driver: Silicon Laboratories WFx Wi-Fi linux driver source code ) driver to wp76xx module.
I got those error in dmesg after I had insmod the driver.
wf200.zip (3.9 MB)

Hi T_a,

This driver is provided by SiliconLabs so it’s is out of our scope. You should post the topic in SiliconLabs forum for support.

The disappearance of ttyUSB0 may be due to a conflict between SiliconLabs driver and MBPL driver. You can use the commands below to remove MBPL driver:

sudo rm /lib/modules/$(uname -r)/kernel/drivers/usb/serial/usb_wwan.ko
sudo rmmod qcserial
sudo rmmod cdc_mbim

Then reboot Linux.