Hi ShapShifter,
The handshake was removed...
I'm sad to see this go, I made extensive use of that signal in my projects.
Any exemple in C/C++ or python? Thanks
by:
In the same way the serial communication of the monitor by the micro USB and the GPIO 6 of the processor have been removed from the header.
I meant that D+/D-, LED2, and GP6 have been removed from the J9 header (Vin,5V etc...) off Rev1.
In the corner near the USB. The signals were visible on the header but not on the schematic...
Regarding the wifi, thanks to your precision, then it is not P4_TX / RX that is used but directly the antenna "ANT1" which, unless I'm mistaken, did not appear on the diagram of revision 1.
The two companies have reconciled and recombined, and now we have the Rev 2
it's good to read it but so the revision 2 is not a celebration at the height of the event ...especially speaking of the OpenWrt / Lede distribution and its updates.
upgrade firmware openwrt yun rev2
and
Finally, it is true that the RPI is very popular and well documented.
If it is ideal for small applications like Multimedia / IOT / PC / Server / Retrogaming ...,
it must still add additional modules (cap / shield) to have professional-level physical applications while a microcontroller does it natively (capture modules, interrupts, high speed PWM, SPI / UART / I2C, timer and especially real time and 6 ADC...)
I will also recommend the Beagle Bone Black / green for linux enthusiasts and the Nucleo / STM32 + Cube for microcontroller programmers in C / C +.
But I chose the yun because I was a beginner and not at all comfortable with linux to make IOT
But we go beyond the scope of this topic 
Thank you anyway!