I have eTrex 20 with a classic problem to stuck on Garmin logo. No problem with force USB and preboot!
In USB mode file system was checked, cleared and I do not have any problem.
In preboot mode the lucky do not want to hurry to me. Only on SW 2.80 RGN (the last existence of working SW in device) either Original or Cure have some progress but unit stuck after beginning update without a success. I had tried to use the service SW from support on garmin.de with attempt to go in preboot without batteries with holding the Power button but it is not work.

What can I do with this creature at next step of undocumented torture?