There are no screws holding the dongle together; the top and bottom of the case simply snap together. The RK2928 is underneath a small heat spreader. Next to it is a Spectek PE937-15E 256MB DDR3 chip. the rest of the components appear to be for power regulation.
On the bottom of the board is a Winbond serial flash chip and a Realtek rtl8188ETV USB wifi module. Small pads labeled TX, RX, and GND are visible near the edge of the board. They are obviously for a serial console. I soldered some 30AWG wire-wrap wire to the pads, and to some 0.1" header pins. With my soldering iron I melted an opening in the plastic case where I hot glued the header pins.
After putting the dongle back together, I connected the serial console to a USB-TTL serial adapter, and powered up the module. I could see the Rx LED on the serial module flickering, indicating it was receiving console output data. I started a terminal program, and was not seeing anything when I tried 9600 and 19,200bps. Then I remembered my logic analyzer has a serial baud rate detection. I hooked it up, ran a capture while the dongle was booting, and found the baud rate was 115,200kbps.
After setting the terminal program to 115,200, I could see what I recognized as the console output of a Linux kernel. When the output stopped, I saw a "#" indicating a root shell prompt - no password required. However the prompt wouldn't last long before the dongle seemed to reboot and repeat the start-up console output.
I first checked the board to make sure nothing was shorting from the connections I made to the serial port pads. I then used a home-made USB cable with exposed power connections to measure the voltage. I found the voltage was briefly dipping below 4.5V when the dongle was rebooting. The dongle's peak power draw was too much for the PC USB port. My solution was a 220uF capacitor connected to my home-made USB cable. With the capacitor added, the voltage stayed above 4.8V, and there were no reboots.
Picuntu Linux very difficult.