Hi Daniel,
I hope you are doing great.
How does SOC do Flash Programmer?
Our EVB provides 2 different ways to program the JN5169, using the LPC or the FTDI. You could select depending on the jumper set up of the JP7 and JP4.

In this case, the ISP_TX_TRGT and ISP_RX_TRGT are connected to the PIO8/PIO9(TX/RX).

For a better reference, you could look at the K32W Datasheet.
Regards,
Mario