My requirement need to use double of the number of UniPi I/O port.
Can I use UniPi as 2nd I/O extension board without 2nd Raspberry PI?

If yes, How to connect the 1st UniPi board to 2nd UniPi board.

1. 1 Wire as red line color or
2. I2C Wire as blue line color

As Picture,

https://s17.postimg.org/ow01n3pcf/unnamed_1.png