makefiles/tools: enhance miniterm path finding in serial.inc.mk [backport 2026.04]

[AnnsAnns]

Backport of #22208

Contribution description

Apparently miniterm likes to change the executable name. In very old versions it was miniterm.py, then it was miniterm and now (version 3.5 and higher) it is pyserial-miniterm.

This change enhances the path discovery to select the right one.

Testing procedure

Make sure you have (a recent version of) pyserial installed:

cbuec@W11nMate:~/RIOTstuff/riot-vanilla/RIOT$ pip show pyserial
Name: pyserial
Version: 3.5
Summary: Python Serial Port Extension
Home-page: https://github.com/pyserial/pyserial
Author: Chris Liechti
Author-email: cliechti@gmx.net
License: BSD
Location: /usr/lib/python3/dist-packages
Requires: 
Required-by: adafruit-nrfutil

Run your favorite application with RIOT_TERMINAL=miniterm.

Behavior on master:

cbuec@W11nMate:~/RIOTstuff/riot-vanilla/RIOT$ RIOT_TERMINAL=miniterm BOARD=nrf52840dk make -C tests/sys/shell flash term -j
make: Entering directory '/home/cbuec/RIOTstuff/riot-vanilla/RIOT/tests/sys/shell'
Building application "tests_shell" for "nrf52840dk" with CPU "nrf52".

"make" -C /home/cbuec/RIOTstuff/riot-vanilla/RIOT/pkg/cmsis/ 
...
J-Link>exit

Script processing completed.

Terminal program miniterm is required but not found in PATH.  Aborting.
make: *** [/home/cbuec/RIOTstuff/riot-vanilla/RIOT/tests/sys/shell/../../../Makefile.include:869: term] Error 1
make: Leaving directory '/home/cbuec/RIOTstuff/riot-vanilla/RIOT/tests/sys/shell'

Behavior with this PR:

cbuec@W11nMate:~/RIOTstuff/riot-vanilla/RIOT$ RIOT_TERMINAL=miniterm BOARD=nrf52840dk make -C tests/sys/shell flash term -j
make: Entering directory '/home/cbuec/RIOTstuff/riot-vanilla/RIOT/tests/sys/shell'
Building application "tests_shell" for "nrf52840dk" with CPU "nrf52".

"make" -C /home/cbuec/RIOTstuff/riot-vanilla/RIOT/pkg/cmsis/ 
...
J-Link>exit

Script processing completed.

pyserial-miniterm --eol LF "/dev/ttyACM0" "115200"  
--- Miniterm on /dev/ttyACM0  115200,8,N,1 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
main(): This is RIOT! (Version: 2026.04-devel-410-gecc128-pr/miniterm)
test_shell.
>

Issues/PRs references

Found while testing #22207.

Declaration of AI-Tools / LLMs usage:

AI-Tools / LLMs that were used are:

• none

[riot-ci]

Murdock results

✔️ PASSED

58a4609 treewide: update documentation regarding miniterm

Success	Failures	Total	Runtime
1	0	1	01m:19s

Artifacts

• Documentation preview

[crasbe]

Please rebase :)

[AnnsAnns]

My brain instantly rebased based on master, we, ofc, don't want to rebase on master here. Fixed now 👍

[AnnsAnns]

Crasbe doesn't want this to be merged 🤨

[crasbe]

We'll have to queue this manually once the next PR on the master queue is merged, otherwise it'll have to be aborted and re-queued anyways.

[AnnsAnns]

Oh, Murdock can't handle multiple merge queues?

[crasbe]

Oh, Murdock can't handle multiple merge queues?

Yes and no, since this is on a different branch, both will be in the Murdock list and GitHub counts that as "running". With our current CI situation, having two merges running at the same time will result in the second merge being cancelled due to inactivity after 6 hours.

So this PR will have to be added manually to the merge queue so that we don't hit that 6h limit, so around ~2 hours after the first merge started.

[crasbe]

That's what I did yesterday/tonight with the Docker PR too before going to sleep 😴

[AnnsAnns]

That's what I did yesterday/tonight with the Docker PR too before going to sleep 😴

True commitment to the craft