If the JTAG connection is not working, try pulling JTAG_TEST high.

This setup, while odd, did work in RIFF BOX V2:
- Connect phone to RIFF BOX and power it on.
- Select TCK 1 MHz speed, and press Analyze JTAG Chain
- If an IDCODE of 0x002C30F7 is detected, switch to RTCK 1 MHZ and try again
- If the same IDCODE sticks, you're good to go!