I just bricked my Guruplug and can consistently do so. :-)
Here the steps:
Take the latest uboot, kernel, rootfs from here http://www.plugcomputer.org/downloads/guru-plug/
Install it as stated here : http://www.newit.co.uk/forum/index.php?topic=417.0
What it says, load the 3 pieces into your nand
Start the plug.
Make sure to step down the network, at least mine needs this to not burn the house :-)
To do this I install ethtool and change my interfaces file.
I also remove the ifplugd pieces from my rc*.d directories
No I can reboot my plug and everything is fine.
If I now do
apt-get install build-essential
and I restart the plug, it gets stuck when it should load the console.
So I end up seeing that my network is connected with 100MBit and my time was updated from the ntpd but these messages are the last I get from the console (serial JTAG connection)
There is a message on the screen [warning] Files in /run will be invisible
In the logiles there is an additional message saying that /dev/console is not availabe.
It looks like /dev/console is just invisible for the bootprocess.
I'm kind of stuck as I don't know where to look next.
I would love to have my Guru running again, but somehow continuously brick it with the install of the build-essential