4700 FPGA JTAG
From embeddedTS Manuals
The four FPGA JTAG pins should be left floating on most base boards. Using these pins to program the System-on-Module's FPGA in the field is not supported.
| WARNING: | FPGA DIO pins are 3.3 V tolerant, driving them above 3.3 V can cause irreparable damage. |