I have tested also current git (f5ea96b1879dba9952c1c3ad12ada5aff1334352), and found that 123 files are ok, 125 files are ok, but 124 files generate "input/output error" (although it does not make the system freeze as it did before)
(note to the moderators: I am the author of the last comment)
I managed to install it but not sure how to do the test... should it be somewhere a mtp-file executable nested in the libmtp directory where I performed the above steps from?
I can try but need some help on how to do it. Can I do it on Ubuntu without uninstalling libmtp packages? How can I be sure to run the version (git) I want? Thx
Also, https://sourceforge.net/p/libmtp/bugs/1830 seems related
...and the discussion lead to think this is related to bug #1808
There is also a thread about this on the list, starting here: https://sourceforge.net/p/libmtp/mailman/message/36592263/
Well, I created https://sourceforge.net/p/libmtp/bugs/1830/ so this one could be closed and deleted. Sorry for trouble.