All very valid points. It seems like the only way to use this device would be over the SPDIF interface. Optic in Analog out.
Firmware revisions, i doubt it can receive them. There is no interface to communicate with the device. There is no logic on it. It is pure DAC/AMP with a DSP in between. If i am wrong, then there has to be an Updater app, to be able to flash new firmware from a PC.
Smartphone app is also a no go, no way of communication between the 2 devices.
Hiss is an engineering oversight. If someone with multiple IEMs could test and see if it is persistent on all of them. My R1 is 32 ohm, its should not be as sensitive as CA Andromeda or anything else with less than 32 ohms and full BA headphone.
The portable Monolith THX AAA amp does have firmware installed. You can find the firmware version in settings. Having said that, I have not seen a firmware update like there is for the desktop Monolith THX AAA amp (which fixed a reversed phase issue with one of the channels).
As far as hiss goes, there is absolutely none to be heard from my full size cans such as the Sundara or the much more sensitive Creative Aurvana SE. My ears are sensitive enough to hear hiss from noise cancelling headphones, but I have not been able to hear it at all from the portable THX AAA amp with any headphones I've tried so far. I will have to find my cheap IEMs to see if I can hear any hiss with them, but I don't need an amp with IEMs so it's not a big deal to me if there is.