Help :( Can't connect to printer? no serial tty.

[bootleg-company]

Hi if anyone has any suggestions it would be greatly appreciated. because i'm walking away from this otherwise. Thanks in advance..

I am trying to connect to my 3DP with a BTT skr mini e3 v3 board, to Klipper (running in ubuntu linux deploy), on an xiaomi a2 lite android phone.

• "ls -al /dev/" doesn't find printer's serial just returns ...
  crw-rw-rw-. 1 root root 5, 0 Jan 13 1970 tty
  lrwxrwxrwx. 1 root root 9 Oct 28 16:05 tty0 -> /dev/null

• lsusb returns nothing.

• dmesg did return a line refering to octoprint
  [ 555.584549] type=1400 audit(1730135355.868:295): avc: denied { ioctl } for pid=8195 comm="octoprint" path="socket:[64705]" dev="sockfs" ino=64705 ioctlcmd=8910 scontext=u:r:untrusted_app:s0:c98,c256,c512,c768 tcontext=u:r:untrusted_app:s0:c98,c256,c512,c768 tclass=unix_dgram_socket permissive=1

• "dmesg | grep usb" or "dmesg | grep acm" returns nothing

• i have flashed the sd card following the boards instructions. tried without sd card plugged in.

• I was following instructions in (https://github.com/d4rk50ul1/klipper-on-android) to use the Octo4a for the custom CH34x driver which my phone seems to be lacking.

• octo4a-2.1.0.apk server start fine but it doesn't recognize any serial connection to the printer.

• printer has been connected and operating previously, to an Ubuntu server laptop running klipper via usb .

• otg cable tested working for connecting to usb storage

• tried a couple of different custom and stock android 9+10 roms

• tried multiple usb's that have worked with the laptop

• i have covered/insulated the 5v power on the usb

• i have tried setting SELinux to permissive with an app on F-droid not sure if its actualy working "getenforce" command not found.

[gaifeng8864]

It should be caused by BTT skr mini e3 v3 not being recognized as a cdc ACM device by Android.
There may be two reasons:

1. There is no cdc ACM driver (USB to serial port) on your phone's Android. This usually requires recompiling the Android kernel or separately compiling a cdc ACM driver that is compatible with the current Android kernel.
2. The MCU used on BTT skr mini e3 v3 does not support USBZ to serial port.

[bootleg-company]

BTT skr mini e3 v3 not being recognized as a cdc ACM device by Android. There may be two reasons:

1. There is no cdc ACM driver (USB to serial port) on your phone's Android. This usually requires recompiling the Android kernel or separately compiling a cdc ACM driver

Thanks for the the clarification.