I am trying to remote programming the MCU 56F8037.
I think you use a line driver component to enhance the digital driving capability for example 74VT244A or the other driver and open drain circuit, which are powered by 3.3V power supply. In detail, you can connect each JTAG signal pin to 74VT244A so that the driving capability can be enhanced to enllarge the line length.
Hope it can help you
Is it the ribbon cable that you are extending?
Can you give more details on the problem?
What happens when you try to program?
Some things to try:
Retrieving data ...