Or: The “I cracked it open, so you don’t need to”-series.
I just figured out that there is a firmware upgrade available for Apple’s $29 miniDP->VGA Dongle. Yes, that’s right. That thing isn’t just plastic with some wires. It isn’t just a passive level adaption. It has real hardware inside. In this case, it’s a ST / genesis microchip gm58009. I couldn’t find much information about that thing (can anyone help?), but running strings B4Flasher.efi |objcopy -I ihex -O binary  on the firmware update reveals some secrets: That thing has 64k of firmware, a full debugmode (over some UART, I assume) and, accordings to strings, HDCP, OSD and all kind of video processing support. Picture after the break.