I just changed the plattform and rebuild the applet. Can you try it with the Hap-File I put here?
as for the format, Yes you are right. FG_FORMAT is treated as a packed format. For microDisplay it is simply a hint on how it should handle the data. If you write an SDK-Programm you can still stream out 12Bit packed and after wards interpret it correctly.
In that case you could set the Output format for example to 8Bit and calculate the width like newWidth = width * 12/8.
Than you grab the bigger image and open the content with anything that interprets the data as a 12Bit packed format.
But I'm really curious why it is not working at your end.