You might try the following:
FT-65 R/E EXPAND TX
Turn radio OFF
Press and hold ptt and Tcall (under the ptt)
Turn radio ON
Release the buttons
insert this number 62406665
The radio reboot and now is expanded.
This come from: https://simonthewizard.com/reviews-3/
(search for FT-65) which has been for quite a while and, according to the comments,worked for at least one person.