Can't connect to BBB using serial via USB on Ubuntu 20.04

I’ve just get a brand new BBB circuit with “out of the box” firmware in it, and I faced the strange behavior:

On my Ubuntu host after connecting the mini-USB cable I can get an access to the internal files (so system defines it as external storage), but I can’t establish a working serial port connection.
Here is dmesg output :

[  137.687352] usb 3-1: new high-speed USB device number 5 using xhci_hcd
[  137.836996] usb 3-1: New USB device found, idVendor=1d6b, idProduct=0104, bcdDevice= 4.01
[  137.836998] usb 3-1: New USB device strings: Mfr=3, Product=4, SerialNumber=5
[  137.836999] usb 3-1: Product: BeagleBoneBlack
[  137.836999] usb 3-1: Manufacturer: Circuitco
[  137.837000] usb 3-1: SerialNumber: C0-0618BBBK1B66
[  137.858202] cdc_acm 3-1:1.2: ttyACM0: USB ACM device
[  137.858227] usbcore: registered new interface driver cdc_acm
[  137.858228] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
[  137.858503] usb-storage 3-1:1.4: USB Mass Storage device detected
[  137.858628] scsi host0: usb-storage 3-1:1.4
[  137.858737] usbcore: registered new interface driver usb-storage
[  137.859918] usbcore: registered new interface driver uas
[  137.860216] usbcore: registered new interface driver cdc_ether
[  137.862382] rndis_host 3-1:1.0 eth0: register 'rndis_host' at usb-0000:00:14.0-1, RNDIS device, 38:d2:69:70:21:f8
[  137.862402] usbcore: registered new interface driver rndis_host
[  137.864085] usbcore: registered new interface driver rndis_wlan
[  137.870293] rndis_host 3-1:1.0 enx38d2697021f8: renamed from eth0
[  138.860126] scsi 0:0:0:0: Direct-Access     Linux    File-Stor Gadget 0401 PQ: 0 ANSI: 2
[  138.860423] scsi 0:0:0:0: Attached scsi generic sg0 type 0
[  138.861370] sd 0:0:0:0: Power-on or device reset occurred
[  138.862099] sd 0:0:0:0: [sda] 81920 512-byte logical blocks: (41.9 MB/40.0 MiB)
[  138.862483] sd 0:0:0:0: [sda] Write Protect is off
[  138.862490] sd 0:0:0:0: [sda] Mode Sense: 0f 00 00 00
[  138.862883] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[  138.867217]  sda: sda1
[  138.877972] sd 0:0:0:0: [sda] Attached SCSI removable disk
[  139.209886] FAT-fs (sda1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.

So Ubuntu detects BBB as ttyACM0, but if we try to connect to it via PuTTY/minicom nothing happens: terminal session is just being idle.

faa@anton:~$ minicom -D /dev/ttyACM0 

Welcome to minicom 2.7.1

Compiled on Dec 23 2019, 02:06:26.
Port /dev/ttyACM0, 20:03:44

Press CTRL-A Z for help on special keys

Another part of this problem is BeagleBone web-interface stays unreachable.

faa@anton:~$ ping
PING ( 56(84) bytes of data.
--- ping statistics ---
6 packets transmitted, 0 received, 100% packet loss, time 5125ms

faa@anton:~$ ping
PING ( 56(84) bytes of data.
--- ping statistics ---
25 packets transmitted, 0 received, 100% packet loss, time 24583ms

I can’t ping no one of stated IP addresses from Ubuntu laptop.

The funny thing is, I can do all the thing mentioned above from the Windows 10 Host after all necessary drivers being installed. So the circuit itself and the USB cable are definitely not the key to the problem.

Can anybody help me please?

is user faa part of the dialout group?


not 100% sure, but I believe that RNDIS is no longer supported by linux… I keep an ancient laptop just for this purpose.

FYI: Linux dropping support for RNDIS...

I did not know that it is an Microsoft protocol… maybe try with a windows machine?

good luck

Yes, it is.

Yeah it worked on Windows machine.
But in replies for this thread is was told that

Every image has two usb network end points, RNDIS and NCM. Only Apple/Linux have been actively using NCM.

So I assume that shouldn’t be a problem

Gr8 … glad to hear that you had a workaround.

I’m ignorant of NCM, for me, 20.04 didn’t work, but 18.04 did … as far as I looked into it.