Re Firmware, Try and find an old fashioned PC with one of those old fashioned real RS232 ports. I tried to load firmeware to a G91 through a USB-serial connection and it failed. Through a real RS232 port (Comm1) it ran no problem.

Best of Luck

Current Mismash of components :
1) TV System Living Room
2) Media Streaming Kitchen
3) Cinema System
4) Media Streaming Room 2
5) Other stuff in the post...