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I have a USB modem that sometimes enumerates wrong and creates a false device in /dev. How do I remove that bogus device ? How do I force renumeration without rebooting ?

When the modem works correctly, it produces this:

crw-rw---T 1 root dialout 166, 0 Oct 15 21:51 /dev/ttyACM0
crw-rw---T 1 root dialout 166, 1 Oct 15 21:50 /dev/ttyACM1
crw-rw---T 1 root dialout 166, 2 Oct 15 21:50 /dev/ttyACM2
crw-rw---T 1 root dialout 166, 3 Oct 15 21:50 /dev/ttyACM3
crw-rw---T 1 root dialout 166, 4 Oct 15 21:50 /dev/ttyACM4
crw-rw---T 1 root dialout 166, 5 Oct 15 21:50 /dev/ttyACM5

When there's a problem, it produces this (note the curious first line):

-rw-r--r-- 1 root root         8 Oct 31 17:17 /dev/ttyACM0
crw-rw---T 1 root dialout 166, 1 Oct 31 16:18 /dev/ttyACM1
crw-rw---T 1 root dialout 166, 2 Oct 31 16:18 /dev/ttyACM2
crw-rw---T 1 root dialout 166, 3 Oct 31 17:17 /dev/ttyACM3
crw-rw---T 1 root dialout 166, 4 Oct 31 16:18 /dev/ttyACM4
crw-rw---T 1 root dialout 166, 5 Oct 31 16:18 /dev/ttyACM5
crw-rw---T 1 root dialout 166, 6 Oct 31 16:18 /dev/ttyACM6

How do I fix this ?

3
  • please format the printouts as code
    – jsotola
    Nov 2, 2021 at 1:35
  • the first line appears to be a regular file ... what is the content of that file?
    – jsotola
    Nov 2, 2021 at 1:40
  • unplug modem, remove that file, plug in modem
    – Bravo
    Nov 2, 2021 at 2:40

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