The *.pdt (where * is same name as a mdl file is indeed
an intel hex file.
If converted to a binary, its 64 Kb (nice number).
It looks like the program for the remote.
(all system screen texts are in it)

The bootloader must be protected, if not any upload
failure would force people to send the remote back.

Well after disassembling the code, we should find out :-)

So what processor is in it?
Anyone knows what processor has a 0x8D jmp instruction?