Hi, hasu san.
I've tested updated firmware.
It looks like new firmware broke the inhibit key repeat feature on new type keyboard.
looked debug via hid_listen.exe, keyboard type data ("A0 80") was coming when "pc98_inhibit_repeat()".
This is why key repeat wasn't configure properly.
I'm not master of ATMEGA32U4 or C/C++, but tried investigate what's going on.
I tried add more "code = pc98_wait_response();" to "pc98_is_newtype()".
connecting Arduino to PC, CMP-6D1Y7 sends "FB FA A0 80" when received "9F".
I don’t get it why there's "FB". Is that a some kind of ACK?
resetting connected Arduino, CMP-6D1Y7 sends "FA A0 80" normally. there's no "FB".
It may needs some workaround that allow "FB FA" as ACK.