If even 1% of users brick their receiver, we would have a serious problem! For most, the TTL header will only be used for recovery in place of having to send the unit back to the distributor like must be done with the Manhattan RS1933. In these cases where the user is savy enough to open the case, connect to a header and configure their PC, these types of users are typically the same ones that would modify hardware to serve their purpose.
For the advanced user who wishes to maintain the serial connection and is not concerned with modifying the case and voiding the warranty, I would suggest to drill out the rear panel marking (to the left of the Power IN port) and feed the USB/TTL cable through, secure at the entry point so it doesn't twist or pull out, then connect to the header.
As Primestar31 pointed out, the demand would be niche for an outer case connection. I would encourage any 3rd party to provide a hardware and software solution to leverage serial communication with the microHD. I have seen several 3rd party solutions for scanners and radios that are pretty amazing!
I will provide as much guidance as possible to any team who wishes to take serial com with the microHD to the next level! Support could include replacement case top covers...
