For some reason in the flash downloads a file has been named incorrectly.
You need to rename 'ucl2.txt' to 'ucl2.xml'
For example in the linux image download the file is located:
Linux\tools\Mfgtools-Rel-4.1.0_130816_MX6DL_UPDATER\Profiles\MX6DL Linux Update\OS Firmware
This file also needs to be renamed in the Android flash download.
For the debug serial, I'm connected to it via TTL with a CP2102 (CP2102-GM - SILICON LABORATORIES - USB-TO-UART BRIDGE, 3.6V, MLP | Farnell UK) on a USB board.
On Windows Putty (PuTTY: a free telnet/ssh client) works as a good serial console. Flow control should be set to off and the bitrate to 115200.
Does that answer your question ?