Apologies, I thought that I already replied on the progress of the 64-bit driver. Mixed news, it is working but not well.
Embarcadero, the current owners of Delphi (after Borland) have a free version of Delphi for hobbyists. That includes a 64-bit version.
With it I managed to import and recompile both projects (FTDI driver + camera driver) but nothing worked. Our code was written before Delphi was migrated to unicode. I had to manually change every string and all string functions and eventually I managed to talk to the camera.
Unfortunately the new driver keeps crashing and debugging a DLL called from a DLL (which is called and calling another DLL) is not that trivial. And things being written in two different programming languages (c# and Delphi) does not help either.
I have not given up but finding where the problem is may take a while. It probably is something simple... but I still have to find it
By the way, the main DLL went from 300kB to 1.6MB in size, simply by recompiling it with the new Delphi compiler
I am not sure if there will be more issues once it is working properly.