I just came to the same problem on Mint 20.1 when I tried to connect my Garmin eTrex Vista HCx with GpsBabel.
"gpsbabel -i garmin -f usb:-1" always causes the message "Could not start session in a reasonable number of tries"!
All my researches in the internet have not brought a solution.
Although my eTrex is now quite old it still works perfectly. A big advantage of this model is the fact that I can use it with rechargeables as well as with normal batteries.
By the way: On my old notebook with Ubuntu 16.04 32bit the connection between GpsBabel and eTrex workes fine.
Good evening,
I just came to the same problem on Mint 20.1 when I tried to connect my Garmin eTrex Vista HCx with GpsBabel.
"gpsbabel -i garmin -f usb:-1" always causes the message "Could not start session in a reasonable number of tries"!
All my researches in the internet have not brought a solution.
Although my eTrex is now quite old it still works perfectly. A big advantage of this model is the fact that I can use it with rechargeables as well as with normal batteries.
By the way: On my old notebook with Ubuntu 16.04 32bit the connection between GpsBabel and eTrex workes fine.
Regards