I'm also investigating how to make lightpack work with fire tv.
For what I have seen, when I plug in on the fire tv usb I get this on dmesg:
<6>[ 1566.539337] usb 4-1.3: new full-speed USB device number 5 using msm_hsusb_host
<6>[ 1566.651306] usb 4-1.3: New USB device found, idVendor=1d50, idProduct=6022
<6>[ 1566.651367] usb 4-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=220
<6>[ 1566.651397] usb 4-1.3: Product: Lightpack
<6>[ 1566.651428] usb 4-1.3: Manufacturer: lightpack.googlecode.com
<6>[ 1566.651428] usb 4-1.3: SerialNumber: ---------hidden----------
<3>[ 1566.655242] generic-usb 0003:1D50:6022.0006: claimed by neither input, hiddev nor hidraw
<6>[ 1572.450103] usb 4-1.3: USB disconnect, device number 5
<6>[ 1576.009277] usb 4-1.2: new full-speed USB device number 6 using msm_hsusb_host
<6>[ 1576.121429] usb 4-1.2: New USB device found, idVendor=1d50, idProduct=6022
<6>[ 1576.121459] usb 4-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=220
<6>[ 1576.121520] usb 4-1.2: Product: Lightpack
<6>[ 1576.121520] usb 4-1.2: Manufacturer: lightpack.googlecode.com
<6>[ 1576.121551] usb 4-1.2: SerialNumber: -------hidden-----------
<3>[ 1576.127929] generic-usb 0003:1D50:6022.0007: claimed by neither input, hiddev nor hidraw
<6>[ 1735.273437] usb 4-1.2: USB disconnect, device number 6
<6>[ 1989.729248] usb 4-1.2: new full-speed USB device number 7 using msm_hsusb_host
<6>[ 1989.841064] usb 4-1.2: New USB device found, idVendor=1d50, idProduct=6022
<6>[ 1989.841094] usb 4-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=220
<6>[ 1989.841125] usb 4-1.2: Product: Lightpack
<6>[ 1989.841125] usb 4-1.2: Manufacturer: lightpack.googlecode.com
<6>[ 1989.841156] usb 4-1.2: SerialNumber: ------hidden---------
<3>[ 1989.844238] generic-usb 0003:1D50:6022.0008: claimed by neither input, hiddev nor hidra
When I open the prismatik app I can see some time while the app is open, some times after I close it that the lightpack is indeed being detected, with a toast stating:
found Lightpack/dev/bus/usb/004/007
Or something like that.
I think the needed modules maybe are missing or are specific to only some kinds of HID. So further investigation is needed.