External UART on Colibri IMX6 under WinCE

Whats the recommend way to have a total of 8 uarts (possibly up to 12) available on Colibri IMX6 under WEC7 or possible WEC2013?
Product is very price sensitive and high volume.
Only 2 UARTs need to be fully feature others are just RX/TX.
1x USB Host and 1x OTG need to be available external.

About the only reasonable solution I see is

  • use the i.MX6’s UARTs (I think there are 4?)
  • Add an FTDI USB-to-Serial converter like the FT4232H, because there are FTDI drivers for WinCE
    • There might be cheaper solutions like the CH340G, but probably one needs to write his own driver, and quality and the longterm availability are unclear.
  • A USB hab is required in order to keep 1USBH + 1 USBOTG
  • The hub might be saved, if it is acceptable that the USB-UARTs are not available while USBOTG is connected (use a kind of a multiplexer/analog switch instead of a hub).