Has anyone had any luck updating to firmware ver. 1.7 using a USB Blaster you put together yourself. Everything (except power) is wired according to the pin out in the documentation at http://etim.net.au/nesrgb/background_fault/. The board is being powered by the NES.
I received the following error:
Error (209040): Can't access JTAG chain
Error (209053): Unexpected error in JTAG server -- error code 44
Error (209012): Operation failed
yeah - you have to wire up the power wire and ground because the power wire's main function is to sense that the nesrgb has power and to tell the usb blaster that. - its function is Not to power the nesrgb.
The first time i programmed a board i learned that too from someone else.
Other than that - you should be able to program it.
You can easily modify the USB Blaster to provide the 3.3V needed for the NESRGB. If you open up the USB Blaster you'll find an unused through-hole marked "3V3", just solder a wire from there to pin 4 of the JTAG harness and you're good. This way you can program the NESRGB without having to turn on the NES.