BeagleBone Black
Today I received my BeagleBone Black! For 45$ you get more power and even HDMI. There is also a serial debug port now on a distinct header connected to UART0 of the CPU. The user can connect to this serial port with a TTL converter (like the FTDI-USB-Cables) and a terminal emulator. Set the baudrate of 115200 and you should be able to see U-Boot, the boot process and a login prompt in the end. Everything worked fine, except when I tried to connect using SSH it failed with an error:
$ ssh 192.168.7.2 ssh_exchange_identification: Connection closed by remote host
I could no figure out how to resolve this on the currently running firmware so I followed a tip on the mailing list to just upgrade the firmware. On linux this is normally a fairly easy process, one has just to decompress the image and pipe it to a SD-Card.
unxz --stdout BBB-eMMC-flasher-2013.04.13-DDR3-400MHz.img.xz | dd of=/dev/mmcblk0