OK so...
you maybe have a faulty one but first you should consider to start from the beginning and clear your eeprom then install the firmware, open the GUI and reset (r370 have already MinimOSD as default OSD)
then make sure you have communication between them by changing a value (wherever you want or need to change) write to the board and read, check your changed value/values or functions you have selected.
To complete upload your font map again and test.
If the problem persists you should consider to buy one more OSD... :(
To be honest, I never tested those HK ones and I do not know anyone who have one of those.
Hope you get it running.
Have fun,
-KV