w/ Raspberry Pi - Bullseye, Full, 64bit

I have been using /dev/ttyUSB2 every day for the last month.Today I changed it to /dev/ttyUSB3 and now can't get it to change back.


  • works and loads config file

sudo minicom

  • "minicom: cannot open /dev/ttyUSB3: No such file or directory" because it's still getting the modem setting from somewhere else entirely.

sudo minicom -s

  • saves file properly but the file isn't used on startup

sudo minicom configuration /etc/minicom/minirc.dfl

  • "minicom: cannot open /dev/modem: No such file or directory"

/dev/ttyUSB3 persists even after using: sudo apt-get purge --autoremove minicom

/etc/minicom/minirc.dfl :

# Machine-generated file - use "minicom -s" to change parameters.

pu port /dev/ttyUSB2

1 Answer 1


Use minicom -s to set the serial port.

minicom -s will set the current user's configuration.

sudo minicom -s will set root's configuration.

  • "minicom -s" works, but "sudo minicom" is broken. It doesn't save to its own root config anymore, but still loads the one with the incorrect port. Saving worked until the non-existing port was saved, but now saving doesn't work. Again - "minicom -s" does work. May 3, 2023 at 11:47

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