Don't worry, they cut all the trees down. Got to pack that lot with the biggest mcmansion that will fit.
If you open it up, there is nothing stopping you from reprogramming the flash chips.
It's based on Freescale's LTIB, which I also worked on when I worked for them. But, it's highly customized. Freescale hasn't really maintained LTIB for some time, despite continuing to use it as the base for their BSPs. Something like Debian is much too bloated for what the radios are expected to work it. The same system is used for the simpler non-touch radios in other GM vehicles. It's an ARM9 based iMX25, running at I think 380 MHz, with 32 MB of RAM. The framebuffer comes out of the RAM too. I managed to get it to boot from power on (or rather CAN bus wakeup pulse) through u-boot, through the kernel startup, to system startup and daemons running and have userspace application code start in around 250 ms. Getting the backup camera working in <1 second is an important requirement. The ARM9 as a VIVT cache, which forces a cache flush on each context switch, making it quite slow. If one used udev like a normal Linux distro, it takes something like 3 seconds just for udev to populate
The radios are not designed to let you easily root or put different software on. However, stopping someone who has physical access to the radio from hacking it wasn't a very high priority. By default LTIB gives you a blank password root account and a telnet daemon configured to allow root logins! I got rid of that and made it ssh only. I don't know if the final production firmware still has ssh running or not. The iMX53 processor used in the CUE system doesn't have secure boot like some other iMX processors. Freescale's iMX line is actually composed of multiple utterly different families of ARM based SoCs based on different IP. So you can easily hack it with a flash programmer.
I don't know of any easter eggs.... GM isn't the kind of company that would look kindly on that. However, unless someone managed to fix it, you can lockup the DVD player with the "Justice League: Starcrossed" DVD a few minutes in. After the alien ship shoots at some jets. It's not the DVD player, but the video overlay on the iMX53 that has locked up.
TIn both cases, better training and adhering to safety protocols would have saved lives
Saved lives at Three Miles Island? Who died?
"The series will begin with the 1996 first book, "A Game of Thrones," and the intention is for each novel (they average 1,000 pages each) to fuel a season's worth of episodes. Martin has nearly finished the fifth installment, but won't complete the seven-book cycle until 2011."
Martin's journal (http://grrm.livejournal.com/11326.html) also has some comments about the series.